WorldWideScience

Sample records for plasma motor generator

  1. Motor/generator

    Science.gov (United States)

    Hickam, Christopher Dale

    2008-05-13

    A motor/generator is provided for connecting between a transmission input shaft and an output shaft of a prime mover. The motor/generator may include a motor/generator housing, a stator mounted to the motor/generator housing, a rotor mounted at least partially within the motor/generator housing and rotatable about a rotor rotation axis, and a transmission-shaft coupler drivingly coupled to the rotor. The transmission-shaft coupler may include a clamp, which may include a base attached to the rotor and a plurality of adjustable jaws.

  2. 350 KVA motor generators

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    Each logic circuit in the central computers consumes only a fraction of a watt: however, the final load constituted by many such circuits plus peripheral equipment is nearly half a million watts. Shown here are two 350 KVA motor generators used to convert 50 Hz mains to 60 Hz (US standard). Flywheels on the M.G. shafts remove power dropouts of up to 0.5 s.

  3. Solid expellant plasma generator

    Science.gov (United States)

    Stone, Nobie H. (Inventor); Poe, Garrett D. (Inventor); Rood, Robert (Inventor)

    2010-01-01

    An improved solid expellant plasma generator has been developed. The plasma generator includes a support housing, an electrode rod located in the central portion of the housing, and a mass of solid expellant material that surrounds the electrode rod within the support housing. The electrode rod and the solid expellant material are made of separate materials that are selected so that the electrode and the solid expellant material decompose at the same rate when the plasma generator is ignited. This maintains a point of discharge of the plasma at the interface between the electrode and the solid expellant material.

  4. Electrostatic generator/motor configurations

    Science.gov (United States)

    Post, Richard F

    2014-02-04

    Electrostatic generators/motors designs are provided that generally may include a first cylindrical stator centered about a longitudinal axis; a second cylindrical stator centered about the axis, a first cylindrical rotor centered about the axis and located between the first cylindrical stator and the second cylindrical stator. The first cylindrical stator, the second cylindrical stator and the first cylindrical rotor may be concentrically aligned. A magnetic field having field lines about parallel with the longitudinal axis is provided.

  5. Development of motorized plasma lithography for cell patterning.

    Science.gov (United States)

    Deguchi, Shinji; Nagasawa, Yohei; Saito, Akira C; Matsui, Tsubasa S; Yokoyama, Sho; Sato, Masaaki

    2014-03-01

    The micropatterning of cells, which restricts the adhesive regions on the substrate and thus controls cell geometry, is used to study mechanobiology-related cell functions. Plasma lithography is a means of providing such patterns and uses a spatially-selective plasma treatment. Conventional plasma lithography employs a positionally-fixed mask with which the geometry of the patterns is determined and thus is not suited for producing on-demand geometries of patterns. To overcome this, we have manufactured a new device with a motorized mask mounted in a vacuum chamber of a plasma generator, which we designate motorized plasma lithography. Our pilot tests indicate that various pattern geometries can be obtained with the control of a shielding mask during plasma treatment. Our approach can thus omit the laborious process of preparing photolithographically microfabricated masks required for the conventional plasma lithography.

  6. PS main supply: motor-generator set.

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    In picture 04 the motor is on the right in the background and the main view is of the generator. The peak power in each PS cycle drawn from the generator, up to 96 MW, is taken from the rotational kinetic energy of the rotor (a heavy-weight of 80 tons), which makes the rotational speed drop by only a few percent. The motor replenishes the average power of 2 to 4 MW. Photo 05: The motor-generator set is serviced every year and, in particular, bearings and slip-rings are carefully checked. To the left is the motor with its slip-rings visible. It has been detached from the axle and moved to the side, so that the rotor can be removed from the huge generator, looming at the right.

  7. Trapped field internal dipole superconducting motor generator

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Downers Grove, IL)

    2001-01-01

    A motor generator including a high temperature superconductor rotor and an internally disposed coil assembly. The motor generator superconductor rotor is constructed of a plurality of superconductor elements magnetized to produce a dipole field. The coil assembly can be either a conventional conductor or a high temperature superconductor. The superconductor rotor elements include a magnetization direction and c-axis for the crystals of the elements and which is oriented along the magnetization direction.

  8. Control system for bearingless motor-generator

    Science.gov (United States)

    Kascak, Peter E. (Inventor); Jansen, Ralph H. (Inventor); Dever, Timothy P. (Inventor)

    2010-01-01

    A control system for an electromagnetic rotary drive for bearingless motor-generators comprises a winding configuration comprising a plurality of individual pole pairs through which phase current flows, each phase current producing both a lateral force and a torque. A motor-generator comprises a stator, a rotor supported for movement relative to the stator, and a control system. The motor-generator comprises a winding configuration supported by the stator. The winding configuration comprises at least three pole pairs through which phase current flows resulting in three three-phase systems. Each phase system has a first rotor reference frame axis current that produces a levitating force with no average torque and a second rotor reference frame axis current that produces torque.

  9. 46 CFR 169.675 - Generators and motors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Generators and motors. 169.675 Section 169.675 Shipping... Less Than 100 Gross Tons § 169.675 Generators and motors. (a) Each generator and motor must be fitted... applicable. (10) Type of winding (for direct-current motors). (b) Each vessel of more than 65 feet in...

  10. 46 CFR 129.320 - Generators and motors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Generators and motors. 129.320 Section 129.320 Shipping... INSTALLATIONS Power Sources and Distribution Systems § 129.320 Generators and motors. (a) Each generator and motor, except a submersible-pump motor, must be— (1) In an accessible space, adequately ventilated...

  11. Motor-Generator Set, PS Main Supply

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    This is the "new" motor-generator set. It replaced the previous, original, one which had served from the PS start-up in 1959. Ordered in 1965, installed in 1967, it was brought into operation at the beginning of 1968. Regularly serviced and fitted with modern regulation and controls, it still serves at the time of writing (2006) and promises to serve for several more years, as a very much alive museum-piece. See also 6803016 and 0201010.

  12. 46 CFR 120.320 - Generators and motors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Generators and motors. 120.320 Section 120.320 Shipping... and Distribution Systems § 120.320 Generators and motors. (a) Each generator and motor must be: (1) In... generator and motor must be designed for an ambient temperature of 50 °C (122 °F) except that: (1) If...

  13. 49 CFR 229.91 - Motors and generators.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Motors and generators. 229.91 Section 229.91 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....91 Motors and generators. A motor or a generator may not have any of the following conditions: (a)...

  14. 46 CFR 169.666 - Generators and motors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Generators and motors. 169.666 Section 169.666 Shipping... of Less Than 100 Gross Tons § 169.666 Generators and motors. (a) Each vessel of more than 65 feet in...) Each generator and motor must be in a location that is accessible, adequately ventilated, and as dry...

  15. 46 CFR 183.320 - Generators and motors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Generators and motors. 183.320 Section 183.320 Shipping...) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.320 Generators and motors. (a) Each generator and motor must be: (1) In a location that is accessible, adequately ventilated, and as dry...

  16. Electrode geometry for electrostatic generators and motors

    Energy Technology Data Exchange (ETDEWEB)

    Post, Richard F.

    2016-02-23

    An electrostatic (ES) device is described with electrodes that improve its performance metrics. Devices include ES generators and ES motors, which are comprised of one or more stators (stationary members) and one or more rotors (rotatable members). The stator and rotors are configured as a pair of concentric cylindrical structures and aligned about a common axis. The stator and rotor are comprised of an ensemble of discrete, longitudinal electrodes, which are axially oriented in an annular arrangement. The shape of the electrodes described herein enables the ES device to function at voltages significantly greater than that of the existing art, resulting in devices with greater power-handling capability and overall efficiency. Electrode shapes include, but are not limited to, rods, corrugated sheets and emulations thereof.

  17. Optical plasma torch electron bunch generation in plasma wakefield accelerators

    Directory of Open Access Journals (Sweden)

    G. Wittig

    2015-08-01

    Full Text Available A novel, flexible method of witness electron bunch generation in plasma wakefield accelerators is described. A quasistationary plasma region is ignited by a focused laser pulse prior to the arrival of the plasma wave. This localized, shapeable optical plasma torch causes a strong distortion of the plasma blowout during passage of the electron driver bunch, leading to collective alteration of plasma electron trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.

  18. Concurrent word generation and motor performance: further evidence for language-motor interaction.

    Directory of Open Access Journals (Sweden)

    Amy D Rodriguez

    Full Text Available Embodied/modality-specific theories of semantic memory propose that sensorimotor representations play an important role in perception and action. A large body of evidence supports the notion that concepts involving human motor action (i.e., semantic-motor representations are processed in both language and motor regions of the brain. However, most studies have focused on perceptual tasks, leaving unanswered questions about language-motor interaction during production tasks. Thus, we investigated the effects of shared semantic-motor representations on concurrent language and motor production tasks in healthy young adults, manipulating the semantic task (motor-related vs. nonmotor-related words and the motor task (i.e., standing still and finger-tapping. In Experiment 1 (n = 20, we demonstrated that motor-related word generation was sufficient to affect postural control. In Experiment 2 (n = 40, we demonstrated that motor-related word generation was sufficient to facilitate word generation and finger tapping. We conclude that engaging semantic-motor representations can have a reciprocal influence on motor and language production. Our study provides additional support for functional language-motor interaction, as well as embodied/modality-specific theories.

  19. Modelling of new generation plasma optical devices

    Directory of Open Access Journals (Sweden)

    Litovko Irina V.

    2016-06-01

    Full Text Available The paper presents new generation plasma optical devices based on the electrostatic plasma lens configuration that opens a novel attractive possibility for effective high-tech practical applications. Original approaches to use of plasma accelerators with closed electron drift and open walls for the creation of a cost-effective low-maintenance plasma lens with positive space charge and possible application for low-cost, low-energy rocket engine are described. The preliminary experimental, theoretical and simulation results are presented. It is noted that the presented plasma devices are attractive for many different applications in the state-of-the-art vacuum-plasma processing.

  20. Motor-Generator powering the PS (Proton Synchrotron) main magnets

    CERN Multimedia

    1983-01-01

    This motor-generator,30 MW peak, 1500 r.p.m.,pulsed power supply for the PS main magnet replaced in 1968 the initial 3000 r.p.m. motor-generator-flywheel set which had served from the PS start-up in 1959 until end 1967. See also photo 8302337 and its abstract.

  1. Permanent-Magnet Motors and Generators for Aircraft

    Science.gov (United States)

    Echolds, E. F.

    1983-01-01

    Electric motors and generators that use permarotating machinery, but aspects of control and power conditioning are also considered. The discussion is structured around three basic areas: rotating machine design considerations presents various configuration and material options, generator applications provides insight into utilization areas and shows actual hardware and test results, and motor applications provides the same type of information for drive systems.

  2. Plasma generation induced by triboelectrification

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Singh, Shailendra Vikram; Michelsen, Poul

    2009-01-01

    A gas discharge plasma can be induced by triboelectrification around a sliding contact. The detailed physical mechanism of triboelectrification is unknown, but an empirical classification scheme can be referred to in practice. It is reported that intense ultra-violet emission from a plasma...

  3. Proton driven plasma wakefield generation in a parabolic plasma channel

    Science.gov (United States)

    Golian, Y.; Dorranian, D.

    2016-11-01

    An analytical model for the interaction of charged particle beams and plasma for a wakefield generation in a parabolic plasma channel is presented. In the suggested model, the plasma density profile has a minimum value on the propagation axis. A Gaussian proton beam is employed to excite the plasma wakefield in the channel. While previous works investigated on the simulation results and on the perturbation techniques in case of laser wakefield accelerations for a parabolic channel, we have carried out an analytical model and solved the accelerating field equation for proton beam in a parabolic plasma channel. The solution is expressed by Whittaker (hypergeometric) functions. Effects of plasma channel radius, proton bunch parameters and plasma parameters on the accelerating processes of proton driven plasma wakefield acceleration are studied. Results show that the higher accelerating fields could be generated in the PWFA scheme with modest reductions in the bunch size. Also, the modest increment in plasma channel radius is needed to obtain maximum accelerating gradient. In addition, the simulations of longitudinal and total radial wakefield in parabolic plasma channel are presented using LCODE. It is observed that the longitudinal wakefield generated by the bunch decreases with the distance behind the bunch while total radial wakefield increases with the distance behind the bunch.

  4. Conceptual design of the KSTAR Motor Generator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang-Hwan, E-mail: kch2004@nfri.re.kr [National Fusion Research Institute, 169-148 Gwahangno, Yusung-gu, Daejeon 305-333 (Korea, Republic of); Kong, Jong-Dea; Eom, Dae-Young; Joung, Nam-Young; Lee, Woo-Jin; Kim, Yang-Soo; Kwon, Myeun [National Fusion Research Institute, 169-148 Gwahangno, Yusung-gu, Daejeon 305-333 (Korea, Republic of); Han, Chul-Woo; Lee, Sel-Ki [Vitzrotech Co. Ltd, 605-2 Seonggok-dong, Danwon-gu, Ansan, Gyeonggi-do 425-833 (Korea, Republic of); Parker, F.J.; Hopkinson, D.; Le Flem, G.D. [Converteam UK Ltd, Leicester Road, Rugby, Warwickshire CV21 1BD (United Kingdom)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The design of the MG which is required to allow the PF MPS to operate at its full power rating has been completed. Black-Right-Pointing-Pointer This system will increase the supply capability to the MPS to 200 MVA, 1.6 GJ and will supply reactive power to the MPS. Black-Right-Pointing-Pointer A VVVF of 12 MW will control the MG and will supply additional active power to the PF MPS in parallel with the MG. Black-Right-Pointing-Pointer The MG will be installed in August 2012. Black-Right-Pointing-Pointer The dummy coil testing will commence in December 2012 with superconducting coil testing scheduled for 2013. - Abstract: The Korean Superconducting Tokamak Advanced Research (KSTAR) superconducting magnet power supply is composed of a Poloidal Field Magnet Power Supply (PF MPS) and a Toroidal Field Magnet Power Supply (TF MPS). When the PF MPS is operated, it requires a large amount of power instantaneously from the KSTAR electric power system. To achieve the KSTAR operational goal, with a long pulse scenario, a peak power of 200 MVA is required and the total power demand for the KSTAR system can exceed 200 MVA. The available grid power is only 100 MVA at the KSTAR site. Increasing the available grid power was uneconomical and inefficient which is why NFRI are installing a Motor Generator (MG). National Fusion Research Institute (NFRI) has made a contract with Vitzrotech and Converteam to design, manufacture and install the MG. Converteam has designed the electromagnetic and mechanical specification of the MG and Variable Voltage Variable Frequency (VVVF) converter. In this paper we discuss the conceptual design, including energy saving and electrical capacity of the MG system and the performance of the MG to satisfy the KSTAR 300 s operation scenario. In addition, the manufacturing and installation plan for the KSTAR MG is discussed.

  5. Hollow-Cathode Source Generates Plasma

    Science.gov (United States)

    Deininger, W. D.; Aston, G.; Pless, L. C.

    1989-01-01

    Device generates argon, krypton, or xenon plasma via thermionic emission and electrical discharge within hollow cathode and ejects plasma into surrounding vacuum. Goes from cold start up to full operation in less than 5 s after initial application of power. Exposed to moist air between operations without significant degradation of starting and running characteristics. Plasma generated by electrical discharge in cathode barrel sustained and aided by thermionic emission from emitter tube. Emitter tube does not depend on rare-earth oxides, making it vulnerable to contamination by exposure to atmosphere. Device modified for use as source of plasma in laboratory experiments or industrial processes.

  6. Physics issues associated with low-beta plasma generators

    Science.gov (United States)

    Borovsky, Joseph E.

    1992-01-01

    Kinetic aspects of MHD generators are explored by examining the propagation of dense, low-beta streams of plasma. Three situations are considered: the basic principles of plasma-stream propagation, the propagation of plasma streams into vacuum, and the propagation of plasma streams into ambient plasmas. These three situations are analogous to plasma generators, plasma generators with vacuum loads, and plasma generators with plasma loads. Kinetic (microphysics) aspects include oscillations of the generator plasma, the effects of diocotron instabilities, the acceleration of particles, the starvation of current systems, and plasma-wave production.

  7. An amplitude modulated radio frequency plasma generator

    Science.gov (United States)

    Lei, Fan; Li, Xiaoping; Liu, Yanming; Liu, Donglin; Yang, Min; Xie, Kai; Yao, Bo

    2017-04-01

    A glow discharge plasma generator and diagnostic system has been developed to study the effects of rapidly variable plasmas on electromagnetic wave propagation, mimicking the plasma sheath conditions encountered in space vehicle reentry. The plasma chamber is 400 mm in diameter and 240 mm in length, with a 300-mm-diameter unobstructed clear aperture. Electron densities produced are in the mid 1010 electrons/cm3. An 800 W radio frequency (RF) generator is capacitively coupled through an RF matcher to an internally cooled stainless steel electrode to form the plasma. The RF power is amplitude modulated by a waveform generator that operates at different frequencies. The resulting plasma contains electron density modulations caused by the varying power levels. A 10 GHz microwave horn antenna pair situated on opposite sides of the chamber serves as the source and detector of probe radiation. The microwave power feed to the source horn is split and one portion is sent directly to a high-speed recording oscilloscope. On mixing this with the signal from the pickup horn antenna, the plasma-induced phase shift between the two signals gives the path-integrated electron density with its complete time dependent variation. Care is taken to avoid microwave reflections and extensive shielding is in place to minimize electronic pickup. Data clearly show the low frequency modulation of the electron density as well as higher harmonics and plasma fluctuations.

  8. Self-organization of dynein motors generates meiotic nuclear oscillations.

    Directory of Open Access Journals (Sweden)

    Sven K Vogel

    2009-04-01

    Full Text Available Meiotic nuclear oscillations in the fission yeast Schizosaccharomyces pombe are crucial for proper chromosome pairing and recombination. We report a mechanism of these oscillations on the basis of collective behavior of dynein motors linking the cell cortex and dynamic microtubules that extend from the spindle pole body in opposite directions. By combining quantitative live cell imaging and laser ablation with a theoretical description, we show that dynein dynamically redistributes in the cell in response to load forces, resulting in more dynein attached to the leading than to the trailing microtubules. The redistribution of motors introduces an asymmetry of motor forces pulling in opposite directions, leading to the generation of oscillations. Our work provides the first direct in vivo observation of self-organized dynamic dynein distributions, which, owing to the intrinsic motor properties, generate regular large-scale movements in the cell.

  9. A non-equilibrium plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Lineberry, J.T.; Wu, Y.C.L.; Martin, J.F. [ERC, Incorporated, Tullahoma, TN (United States)

    1993-12-31

    This paper summarizes research ideas, results and activities on a DOE MHD SBIR entitled: {open_quote}A Light Metal Fueled Nonequilibrium Plasma Generator (NPG){close_quotes}. The NPG is a concept for a device that has the capability of producing a nonequilibrium plasma from metal combustion. The results of preliminary studies on the NPG concept are given. These studies address fundamentals of the NPG including operating concepts of the NPG concept, results of studies on the quality of the plasma that it can produce, and theoretical evaluations of the nonequilibrium ionization process in an MHD disk generator driven by an NPG. A discussion of potential applications for the NPG is given. These applications encompass pulse MHD power, commercial MHD power and disk MHD generator research.

  10. Surface plasma source with saddle antenna radio frequency plasma generator.

    Science.gov (United States)

    Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

    2012-02-01

    A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

  11. Nanomaterial Synthesis Using Plasma Generation in Liquid

    Directory of Open Access Journals (Sweden)

    Genki Saito

    2015-01-01

    Full Text Available Over the past few decades, the research field of nanomaterials (NMs has developed rapidly because of the unique electrical, optical, magnetic, and catalytic properties of these materials. Among the various methods available today for NM synthesis, techniques for plasma generation in liquid are relatively new. Various types of plasma such as arc discharge and glow discharge can be applied to produce metal, alloy, oxide, inorganic, carbonaceous, and composite NMs. Many experimental setups have been reported, in which various parameters such as the liquid, electrode material, electrode configuration, and electric power source are varied. By examining the various electrode configurations and power sources available in the literature, this review classifies all available plasma in liquid setups into four main groups: (i gas discharge between an electrode and the electrolyte surface, (ii direct discharge between two electrodes, (iii contact discharge between an electrode and the surface of surrounding electrolyte, and (iv radio frequency and microwave plasma in liquid. After discussion of the techniques, NMs of metal, alloy, oxide, silicon, carbon, and composite produced by techniques for plasma generation in liquid are presented, where the source materials, reaction media, and electrode configurations are discussed in detail.

  12. Plasma driven neutron/gamma generator

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  13. Nonequilibrium plasma generator (NPG) project - experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Lineberry, J.T.; Wu, Y.C.L.; Lin, B.C. [and others

    1995-12-31

    This paper summarizes research conducted under a DOE MHD SBIR entitled: {open_quotes}A Light Metal Fueled Non-equilibrium Plasma Generator (NPG){close_quotes}. It is a summary paper presenting the idea of the NPG and activities of the NPG SBIR research program along with experimental results from NPG Proof-of-Principle tests. The NPG is an innovative concept for a combustion device that can produce a nonequilibrium plasma. This device bums powdered metal fuel, and it can be used to drive an MHD disk generator pulse power unit or a similar nonequilibrium MHD device or system. The NPG research program was concluded over the past two years under sponsorship of a DOE Phase II SBIR grant. This program focused on addressing fundamental and practical aspects of the NPG concept and its system design. The research included investigation of the physics of the NPG concept through theoretical and experimental studies on the quality of the plasma that it can produce, theoretical evaluations of the nonequilibrium ionization processes in an MHD disk generator driven by an NPG, and experimental validation of the NPG concept in Proof-of-Principle tests. At the conclusion of this research it was determined that the NPG is indeed a viable concept. Results from combustion tests using powdered aluminum fuel reveal that the NPG can produce an extremely hot argon plasma clean enough to support nonequilibrium ionization in an MHD device.

  14. Properties of plasmas generated in microdischarges

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Serrano, E; Hagelaar, G; Callegari, Th; Boeuf, J P; Pitchford, L C [Centre de Physique des Plasmas et Applications de Toulouse (CPAT) Universite Paul Sabatier, Toulouse III, and CNRS UMR 5002 118 route de Narbonne, 31062 Toulouse (France)

    2006-12-15

    We present in this paper a discussion of the properties of plasmas generated in microhollow cathode geometries and in microcathode sustained discharge geometries. The results presented here are derived from models. This work is part of a joint modelling/experimental programme whose objective is the evaluation of the potential of the high-pressure, non-thermal plasmas created in microdischarges (e.g. discharges in small, 100s of micrometre sized geometries) for the production of large quantities of radical species, and in particular oxygen singlet delta (metastable) molecules, O{sub 2}({sup 1}{delta})

  15. Opacity of Shock-Generated Argon Plasmas

    Institute of Scientific and Technical Information of China (English)

    王藩侯; 陈敬平; 周显明; 李西军; 经福谦; 孟续军; 孙永盛

    2001-01-01

    Argon plasmas with uniform density and temperature are generated by a planar shock wave through argon gas. The opacities of argon plasma, covering the thermodynamic states at temperatures of 1.4-2.2eV and in densities of 0.0083- 0.015 g/cm3, are investigated by measuring the emitted radiance versus time at several visible wavelengths. Comparison of the measured opacities with those calculated demonstrates that the average atom model can be used well to describe the essential transport behaviour of photons in argon plasma under the abovementioned thermodynamic condition. A simplified and self-consistent method to deduce the reflectivity R(λ) at the baseplate surface is applied. It demonstrates that the values of R(λ) are all around 0.4 in the experiments, which are basically in agreement with those given by Erskine previously (1994 J. Quant. Spectrosc. Radiat.Transfer 51 97).

  16. Electrical motor/generator drive apparatus and method

    Science.gov (United States)

    Su, Gui Jia

    2013-02-12

    The present disclosure includes electrical motor/generator drive systems and methods that significantly reduce inverter direct-current (DC) bus ripple currents and thus the volume and cost of a capacitor. The drive methodology is based on a segmented drive system that does not add switches or passive components but involves reconfiguring inverter switches and motor stator winding connections in a way that allows the formation of multiple, independent drive units and the use of simple alternated switching and optimized Pulse Width Modulation (PWM) schemes to eliminate or significantly reduce the capacitor ripple current.

  17. Linear moving magnet motor/generator for Stirling engines

    Science.gov (United States)

    Shtrikman, S.; Urieli, I.

    Free piston Stirling cycle machines have many inherent advantages, however suffer from the difficulties of extracting power output and controllability of the free displacer, which is usually driven by gas pressure forces. Modern rare earth samarium cobalt magnets allow the use of moving magnet linear electrical devices. This paper discusses the development and testing of moving magnet devices designed specifically for use with Stirling engines, both for generating electricity and for driving the displacer piston. The generator was used as an output stage of a free piston Stirling engine, and is capable of delivering a power of 500 watts at an estimated efficiency of about 90%. The motor was used to drive the displacer of the same Stirling engine. It was found to be completely controllable in amplitude, phase, and mean position. The relative merits of moving magnet linear motor/generators are discussed.

  18. The use of cold plasma generators in medicine

    National Research Council Canada - National Science Library

    Kolomiiets R.O; Nikitchuk T.M; Hrek O.V

    2017-01-01

    Cold plasma treatment of wounds is a modern area of therapeutic medicine. We describe the physical mechanisms of cold plasma, the principles of therapeutic effects and design of two common types of cold plasma generators for medical use...

  19. The design of a plasma generator used in ships

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The process and condition of arc starting and discharge and heat balance rela-tionship in a plasma generator that takes water as propellant are analyzed. Two questions that must be paid attention to arise, when designing the plasma gen-erator. Water resistance in a plasma generator should be as big as possible, and inductive reactance of electric source should be equal to capacity reactance of plasma generator so that resonance is generated in electric circuit, voltage be-tween two electrodes in the plasma generator reaches the highest value, and arc starting and discharge also occur between electrodes in the plasma generator. When energy that electric source supplies is greater than or equal to the energy required when water becomes plasma, a mixture of plasma and steam ejects from the generator outlet. So it is necessary that cavity between electrodes in the plasma generator should be as big as possible, time that water stays in the plasma gen-erator should be long enough so that water obtains enough energy from the electric source, but resistance of water becomes small and arc starting is not easy to occur. Through manufacturing and experimentes on four kinds of plasma generators as well as the contrast between experimental results, the plasma generator model is established and the plasma generator is manufactured.

  20. A Framework to Describe, Analyze and Generate Interactive Motor Behaviors

    Science.gov (United States)

    Jarrassé, Nathanaël; Charalambous, Themistoklis; Burdet, Etienne

    2012-01-01

    While motor interaction between a robot and a human, or between humans, has important implications for society as well as promising applications, little research has been devoted to its investigation. In particular, it is important to understand the different ways two agents can interact and generate suitable interactive behaviors. Towards this end, this paper introduces a framework for the description and implementation of interactive behaviors of two agents performing a joint motor task. A taxonomy of interactive behaviors is introduced, which can classify tasks and cost functions that represent the way each agent interacts. The role of an agent interacting during a motor task can be directly explained from the cost function this agent is minimizing and the task constraints. The novel framework is used to interpret and classify previous works on human-robot motor interaction. Its implementation power is demonstrated by simulating representative interactions of two humans. It also enables us to interpret and explain the role distribution and switching between roles when performing joint motor tasks. PMID:23226231

  1. The design of a plasma generator used in ships

    Institute of Scientific and Technical Information of China (English)

    WANG XinZhang; YANG JiaXiang; LAN Bo; XU ZuoMing; GAO Ying

    2008-01-01

    The process and condition of arc starting and discharge and heat balance rela-tionship in a plasma generator that takes water as propellant are analyzed.Two questions that must be paid attention to arise,when designing the plasma gen-erator.Water resistance in a plasma generator should be as big as possible,and inductive reactance of electric source should be equal to capacity reactance of plasma generator so that resonance is generated in electric circuit,voltage be-tween two electrodes in the plasma generator reaches the highest value,and arc starting and discharge also occur between electrodes in the plasma generator.When energy that electric source supplies is greater than or equal to the energy required when water becomes plasma,a mixture of plasma and steam ejects from the generator outlet.So it is necessary that cavity between electrodes in the plasma generator should be as big as possible,time that water stays in the plasma gen-erator should be long enough so that water obtains enough energy from the electric source,but resistance of water becomes small and arc starting is not easy to occur.Through manufacturing and experimentes on four kinds of plasma generators as well as the contrast between experimental results,the plasma generator model is established and the plasma generator is manufactured.

  2. GDE2 regulates subtype-specific motor neuron generation through inhibition of Notch signaling.

    Science.gov (United States)

    Sabharwal, Priyanka; Lee, Changhee; Park, Sungjin; Rao, Meenakshi; Sockanathan, Shanthini

    2011-09-22

    The specification of spinal interneuron and motor neuron identities initiates within progenitor cells, while motor neuron subtype diversification is regulated by hierarchical transcriptional programs implemented postmitotically. Here we find that mice lacking GDE2, a six-transmembrane protein that triggers motor neuron generation, exhibit selective losses of distinct motor neuron subtypes, specifically in defined subsets of limb-innervating motor pools that correlate with the loss of force-generating alpha motor neurons. Mechanistically, GDE2 is expressed by postmitotic motor neurons but utilizes extracellular glycerophosphodiester phosphodiesterase activity to induce motor neuron generation by inhibiting Notch signaling in neighboring motor neuron progenitors. Thus, neuronal GDE2 controls motor neuron subtype diversity through a non-cell-autonomous feedback mechanism that directly regulates progenitor cell differentiation, implying that subtype specification initiates within motor neuron progenitor populations prior to their differentiation into postmitotic motor neurons.

  3. Halbach array motor/generators: A novel generalized electric machine

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, B.T.; Post, R.F.; Dreifuerst, G.R.; Bender, D.A. [Lawrence Livermore National Lab., CA (United States)

    1995-02-01

    For many years Klaus Halbach has been investigating novel designs for permanent magnet arrays, using advanced analytical approaches and employing a keen insight into such systems. One of his motivations for this research was to find more efficient means for the utilization of permanent magnets for use in particle accelerators and in the control of particle beams. As a result of his pioneering work, high power free-electron laser systems, such as the ones built at the Lawrence Livermore Laboratory, became feasible, and his arrays have been incorporated into other particle-focusing systems of various types. This paper reports another, quite different, application of Klaus` work, in the design of high power, high efficiency, electric generators and motors. When tested, these motor/generator systems display some rather remarkable properties. Their success derives from the special properties which these arrays, which the authors choose to call {open_quotes}Halbach arrays,{close_quotes} possess.

  4. Motor-generator set of the PS main supply

    CERN Multimedia

    Photographic Service; CERN PhotoLab

    1968-01-01

    Already in 1964, the PS improvement programme included a new main magnet supply with more power for the longer cycles needed for slow extraction at the full energy of 26 GeV. This motor-generator set was installed in 1967 and took up service at the beginning of 1968. Regularly serviced and fitted with modern electronic regulation, it pulses the PS to this day.

  5. Mechanics of torque generation in the bacterial flagellar motor

    CERN Document Server

    Mandadapu, Kranthi K; Berry, Richard M; Oster, George

    2015-01-01

    The bacterial flagellar motor (BFM) is responsible for driving bacterial locomotion and chemotaxis, fundamental processes in pathogenesis and biofilm formation. In the BFM, torque is generated at the interface between transmembrane proteins (stators) and a rotor. It is well-established that the passage of ions down a transmembrane gradient through the stator complex provides the energy needed for torque generation. However, the physics involved in this energy conversion remain poorly understood. Here we propose a mechanically specific model for torque generation in the BFM. In particular, we identify two fundamental forces involved in torque generation: electrostatic and steric. We propose that electrostatic forces serve to position the stator, while steric forces comprise the actual 'power stroke'. Specifically, we predict that ion-induced conformational changes about a proline 'hinge' residue in an $\\alpha$-helix of the stator are directly responsible for generating the power stroke. Our model predictions f...

  6. Thyristor stack for pulsed inductive plasma generation.

    Science.gov (United States)

    Teske, C; Jacoby, J; Schweizer, W; Wiechula, J

    2009-03-01

    A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 micros and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/micros.

  7. Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae

    OpenAIRE

    Sebastian Hückesfeld; Andreas Schoofs; Philipp Schlegel; Anton Miroschnikow; Pankratz, Michael J.

    2015-01-01

    Motor systems can be functionally organized into effector organs (muscles and glands), the motor neurons, central pattern generators (CPG) and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feedin...

  8. Power consumption analysis DBD plasma ozone generator

    Science.gov (United States)

    Nur, M.; Restiwijaya, M.; Muchlisin, Z.; Susan, I. A.; Arianto, F.; Widyanto, S. A.

    2016-11-01

    Studies on the consumption of energy by an ozone generator with various constructions electrodes of dielectric barrier discharge plasma (DBDP) reactor has been carried out. This research was done to get the configuration of the reactor, that is capable to produce high ozone concentrations with low energy consumption. BDBP reactors were constructed by spiral- cylindrical configuration, plasma ozone was generated by high voltage AC voltage up to 25 kV and maximum frequency of 23 kHz. The reactor consists of an active electrode in the form of a spiral-shaped with variation diameter Dc, and it was made by using copper wire with diameter Dw. In this research, we variated number of loops coil windings N as well as Dc and Dw. Ozone concentrations greater when the wire's diameter Dw and the diameter of the coil windings applied was greater. We found that impedance greater will minimize the concentration of ozone, in contrary to the greater capacitance will increase the concentration of ozone. The ozone concentrations increase with augmenting of power. Maximum power is effective at DBD reactor spiral-cylinder is on the Dc = 20 mm, Dw = 1.2 mm, and the number of coil windings N = 10 loops with the resulting concentration is greater than 20 ppm and it consumes energy of 177.60 watts

  9. Scaling of motor cortical excitability during unimanual force generation.

    Science.gov (United States)

    Perez, Monica A; Cohen, Leonardo G

    2009-10-01

    During performance of a unimanual force generation task primary motor cortices (M1s) experience clear functional changes. Here, we evaluated the way in which M1s interact during parametric increases in right wrist flexion force in healthy volunteers. We measured the amplitude and the slope of motor evoked potentials (MEP) recruitment curves to transcranial magnetic stimulation (TMS) in the left and right flexor carpi radialis (FCR) muscles at rest and during 10%, 30% and 70% of maximal wrist flexion force. At rest, no differences were observed in the amplitude and slope of MEP recruitment curves in the left and right FCR muscles. With increasing right wrist flexion force, MEP amplitudes increased in both FCR muscles, with larger amplitudes in the right FCR. We found a significant correlation between the left and right MEP amplitudes across conditions. The slope of right and left FCR MEP recruitment curve was significantly steeper at 70% of force compared to rest and 10% of force. A significant correlation between the slope of left and right FCR MEP amplitudes was found at 70% of force only. Our results indicate a differential scaling of excitability in the corticospinal system controlling right and left FCR muscles at increasing levels of unimanual force generation. Specifically, these data highlights that at strong levels of unimanual force the increases in motor cortical excitability with increasing TMS stimulus intensities follow a similar pattern in both M1s, while at low levels of force they do not.

  10. The Use of Current Generators in Electrical Converter Drives for Stepper Motors

    Directory of Open Access Journals (Sweden)

    Emanoil Toma

    2014-09-01

    Full Text Available This paper presents some ways to realize electrical converters for stepper motor drives. The first part analyzes aspects for unipolar stepper motor and use of constant current generators. The second part present current sources based on peak limiting current trough the inductance of motor coil. A complete drive module for bipolar stepper motor was conceived and simulation results confirm their functionability.

  11. Induction generator-induction motor wind-powered pumping system

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, M.S.; Lyra, R.O.C.; Silva, S.R. [CPDEE - UFMG, Belo Horizonte (Brazil)

    1997-12-31

    The energy storage matter plays an important role in wind-electric conversion systems for isolated applications. Having that in mind, two different approaches can be basically considered: either the immediate conversion of the generated electric energy, as in a water pumping system or electric energy storage for later use, as in a battery charging system. Due to some features such as no need of an external reactive power source and, sometimes, a gearbox, permanent-magnet synchronous generators have been broadly used in low rated power isolated systems. Despite that, system performance can be affected when the generator is feeding an inductive load (e.g., an induction motor) under variable-speed-variable-frequency operational conditions. Since there is no effective flux control, motor overload may occur at high wind speeds. Thus, good system performance can be obtained through additional control devices which may increase system cost. Although being rugged and cheap, induction machines always work as a reactive power drain; therefore, they demand an external reactive power source. Considering that, reactive static compensators appear as an attractive alternative to the cost x performance problem. In addition to that, different control strategies can be used so that system performance can be improved.

  12. Rippled disc electrostatic generator/motor configurations utilizing magnetic insulation

    Energy Technology Data Exchange (ETDEWEB)

    Post, Richard F

    2017-04-04

    Electrostatic generators/motors designs are provided that generally may include a first rippled stator centered about a longitudinal axis; a second rippled stator centered about the axis, a first rippled rotor centered about the axis and located between the first rippled stator and the second rippled stator. A magnetic field having field lines about parallel with the average plane of at least one of the first rippled stator or the second rippled stator is provided with either a Halbach array configuration or a conductor array configuration.

  13. 40 CFR 80.531 - How are motor vehicle diesel fuel credits generated?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How are motor vehicle diesel fuel... (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel... are motor vehicle diesel fuel credits generated? (a) Generation of credits from June 1, 2006...

  14. Submerged electricity generation plane with marine current-driven motors

    Science.gov (United States)

    Dehlsen, James G.P.; Dehlsen, James B.; Fleming, Alexander

    2014-07-01

    An underwater apparatus for generating electric power from ocean currents and deep water tides. A submersible platform including two or more power pods, each having a rotor with fixed-pitch blades, with drivetrains housed in pressure vessels that are connected by a transverse structure providing buoyancy, which can be a wing depressor, hydrofoil, truss, or faired tube. The platform is connected to anchors on the seafloor by forward mooring lines and a vertical mooring line that restricts the depth of the device in the water column. The platform operates using passive, rather than active, depth control. The wing depressor, along with rotor drag loads, ensures the platform seeks the desired operational current velocity. The rotors are directly coupled to a hydraulic pump that drives at least one constant-speed hydraulic-motor generator set and enables hydraulic braking. A fluidic bearing decouples non-torque rotor loads to the main shaft driving the hydraulic pumps.

  15. Submerged electricity generation plane with marine current-driven motors

    Energy Technology Data Exchange (ETDEWEB)

    Dehlsen, James G.P.; Dehlsen, James B.; Fleming, Alexander

    2014-07-01

    An underwater apparatus for generating electric power from ocean currents and deep water tides. A submersible platform including two or more power pods, each having a rotor with fixed-pitch blades, with drivetrains housed in pressure vessels that are connected by a transverse structure providing buoyancy, which can be a wing depressor, hydrofoil, truss, or faired tube. The platform is connected to anchors on the seafloor by forward mooring lines and a vertical mooring line that restricts the depth of the device in the water column. The platform operates using passive, rather than active, depth control. The wing depressor, along with rotor drag loads, ensures the platform seeks the desired operational current velocity. The rotors are directly coupled to a hydraulic pump that drives at least one constant-speed hydraulic-motor generator set and enables hydraulic braking. A fluidic bearing decouples non-torque rotor loads to the main shaft driving the hydraulic pumps.

  16. Plasma antioxidant status and motor features in de novo Chinese Parkinson's disease patients.

    Science.gov (United States)

    Yuan, Yongsheng; Tong, Qing; Zhang, Li; Jiang, Siming; Zhou, Hong; Zhang, Rui; Zhang, Shu; Xu, Qinrong; Li, Daqian; Zhou, Xiaobin; Ding, Jian; Zhang, Kezhong

    2016-01-01

    This study aimed to explore plasma antioxidant status in de novo Chinese Parkinson's disease (PD) patients and investigate its relationship with specific motor features of PD. Sixty-four de novo Chinese PD patients and 40 age- and sex-matched healthy controls were recruited. Each motor feature of PD patients was assessed by unified Parkinson's disease rating scale. Plasma antioxidant status, including plasma level of glutathione (GSH) and plasma activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), was detected using enzyme-linked immunosorbent assay. The relationship between the plasma antioxidant status and motor features of PD was evaluated by Spearman's coefficient. Plasma GSH level and plasma activities of GSH-Px, CAT and SOD of PD patients were lower than those of healthy controls. Moreover, the declining activity of plasma CAT was related with the increasing mean postural instability and gait disorder (PIGD) score and growing age. In contrast, the severity of tremor was positively correlated with plasma SOD activity. Our study demonstrates that the plasma antioxidant status is impaired in de novo Chinese PD patients. The complex relationship between the plasma antioxidant status and different motor features indicates that the antioxidant mechanisms underlying tremor and PIGD of PD may be different.

  17. Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae.

    Directory of Open Access Journals (Sweden)

    Sebastian Hückesfeld

    Full Text Available Motor systems can be functionally organized into effector organs (muscles and glands, the motor neurons, central pattern generators (CPG and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feeding. This basic anatomical scaffold enabled the use of calcium-imaging to monitor the neural activity of motor neurons within the central nervous system (CNS that drive food intake. Simultaneous nerve- and muscle-recordings demonstrate that the motor neurons innervate the cibarial dilator musculature (CDM ipsi- and contra-laterally. By classical lesion experiments we localize a set of CPGs generating the neuronal pattern underlying feeding movements to the subesophageal zone (SEZ. Lesioning of higher brain centers decelerated all feeding-related motor patterns, whereas lesioning of ventral nerve cord (VNC only affected the motor rhythm underlying pharyngeal pumping. These findings provide a basis for progressing upstream of the motor neurons to identify higher regulatory components of the feeding motor system.

  18. Plasma cell treatment device Plasma-on-Chip: Monitoring plasma-generated reactive species in microwells

    Science.gov (United States)

    Oh, Jun-Seok; Kojima, Shinya; Sasaki, Minoru; Hatta, Akimitsu; Kumagai, Shinya

    2017-01-01

    We have developed a plasma cell treatment device called Plasma-on-Chip that enables the real-time monitoring of a single cell culture during plasma treatment. The device consists of three parts: 1) microwells for cell culture, 2) a microplasma device for generating reactive oxygen and nitrogen species (RONS) for use in cell treatment, and 3) through-holes (microchannels) that connect each microwell with the microplasma region for RONS delivery. Here, we analysed the delivery of the RONS to the liquid culture medium stored in the microwells. We developed a simple experimental set-up using a microdevice and applied in situ ultraviolet absorption spectroscopy with high sensitivity for detecting RONS in liquid. The plasma-generated RONS were delivered into the liquid culture medium via the through-holes fabricated into the microdevice. The RONS concentrations were on the order of 10–100 μM depending on the size of the through-holes. In contrast, we found that the amount of dissolved oxygen was almost constant. To investigate the process of RONS generation, we numerically analysed the gas flow in the through-holes. We suggest that the circulating gas flow in the through-holes promotes the interaction between the plasma (ionised gas) and the liquid, resulting in enhanced RONS concentrations. PMID:28176800

  19. Superconducting generators and motors and methods for employing same

    Energy Technology Data Exchange (ETDEWEB)

    Tomsic, Michael J.; Long, Larry

    2017-08-29

    A superconducting electrical generator or motor having a plurality of cryostats is described. The cryostats contain coolant and a first cryostat encloses at least one of a plurality of superconducting coils. A first coil is in superconducting electrical communication with a second coil contained in a second cryostat through a superconducting conduction cooling cable enclosing a conductor. The first cryostat and the second cryostat may be in fluid communication through at least one cryogen channel within the at least one superconducting conduction cooling cable. In other embodiments, none of the plurality of cryostats may be in fluid communication and the cable may be cooled by conduction along the conductor from the first or second cryostat, or from both. The conductor may have different segments at temperatures equal to or above the temperature of the coolant and the superconducting conduction cooling cables may be connected through quick connect fittings.

  20. Plasma generated during underwater pulsed laser processing

    Science.gov (United States)

    Hoffman, Jacek; Chrzanowska, Justyna; Moscicki, Tomasz; Radziejewska, Joanna; Stobinski, Leszek; Szymanski, Zygmunt

    2017-09-01

    The plasma induced during underwater pulsed laser ablation of graphite is studied both experimentally and theoretically. The results of the experiment show that the maximum plasma temperature of 25000 K is reached 20 ns from the beginning of the laser pulse and decreases to 6500 K after 1000 ns. The observed OH absorption band shows that the plasma plume is surrounded by the thin layer of dissociated water vapour at a temperature around 5500 K. The hydrodynamic model applied shows similar maximum plasma temperature at delay times between 14 ns and 30 ns. The calculations show also that already at 14th ns, the plasma electron density reaches 0.97·1027 m-3, which is the critical density for 1064 nm radiation. At the same time the plasma pressure is 2 GPa, which is consisted with earlier measurements of the peak pressure exerted on a target in similar conditions.

  1. An online gait generator for quadruped walking using motor primitives

    Directory of Open Access Journals (Sweden)

    Chunlin Zhou

    2016-11-01

    Full Text Available This article presents implementation of an online gait generator on a quadruped robot. Firstly, the design of a quadruped robot is presented. The robot contains four leg modules each of which is constructed by a 2 degrees of freedom (2-DOF five-bar parallel linkage mechanism. Together with other two rotational DOF, the leg module is able to perform 4-DOF movement. The parallel mechanism of the robot allows all the servos attached on the body frame, so that the leg mass is decreased and motor load can be balanced. Secondly, an online gait generator based on dynamic movement primitives for the walking control is presented. Dynamic movement primitives provide an approach to generate periodic trajectories and they can be modulated in real time, which makes the online adjustment of walking gaits possible. This gait controller is tested by the quadruped robot in regulating walking speed, switching between forward\\backward movements and steering. The controller is easy to apply, expand and is quite effective on phase coordination and online trajectory modulation. Results of simulated experiments are presented.

  2. Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

    Science.gov (United States)

    Studer, P. A. (Inventor)

    1982-01-01

    A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

  3. Self-Bearing Motor-Generator for Flywheels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Self-bearing or ?bearingless? motors perform both motor and bearing support functions but such devices have not yet achieved speeds above 15,000 rpm. The innovation...

  4. Concepts for using trapped-flux bulk high-temperature superconductor in motors and generators

    Science.gov (United States)

    Hull, John R.; Strasik, Michael

    2010-12-01

    We review previous concepts for using bulk high-temperature superconductors (HTSs) in motors and generators and discuss methods for using trapped-flux (TF) HTSs in motors and generators that have been recently investigated in our laboratory. We examine the expected performance of a brushless motor/generator that uses TF bulk HTSs to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium for the stator and rotor cores.

  5. Concepts for using trapped-flux bulk high-temperature superconductor in motors and generators

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R; Strasik, Michael [Boeing Research and Technology, PO Box 3707, MC 2T-50, Seattle, WA 98124-2207 (United States)

    2010-12-15

    We review previous concepts for using bulk high-temperature superconductors (HTSs) in motors and generators and discuss methods for using trapped-flux (TF) HTSs in motors and generators that have been recently investigated in our laboratory. We examine the expected performance of a brushless motor/generator that uses TF bulk HTSs to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium for the stator and rotor cores.

  6. Generator of chemically active low-temperature plasma

    Science.gov (United States)

    Tyuftyaev, A. S.; Gadzhiev, M. Kh; Sargsyan, M. A.; Demirov, N. A.; Spector, N. O.

    2016-11-01

    A new generator of high enthalpy (H 0 > 40 kJ/g), chemically active nitrogen and air plasmas was designed and constructed. Main feature of the generator is an expanding channel of an output electrode; the generator belongs to the class of DC plasma torches with thermionic cathode with an efficiency of 80%. The generator ensures the formation of a slightly divergent plasma jet (2α = 12°) with a diameter of D = 10-12 mm, an electric arc maximum power of 20-50 kW, plasma forming gas flow rate 1.0-2.0 g/s, and the average plasma temperature at an outlet of 8000-11000 K.

  7. The Performance Analysis of Ultra High Speed PM Type Synchronous Motor-Generator for Micro Turbine

    Science.gov (United States)

    Hong, Do-Kwan; Woo, Byung-Chul; Jeong, Yeon-Ho; Koo, Dae-Hyun; Cho, Yun-Hyun

    This paper deals with loss analysis, structural, thermal-fluid and rotordynamics (critical speed and unbalance) which need in developing the motor-generator. This machine has designed of a generator of 800 W, 400 krpm and a starter of 400 W, 200 krpm. The generated losses of motor-generator are derived by magnetic analysis. Thermal-fluid analysis is performed using loss analysis result. The critical speed is extracted by Campbell diagram. Unbalance vibration response analysis enable to predict the expected vibration amplitude by unbalance. The motor-generator is well-developed using the applied several techniques of analysis.

  8. High density plasma production in a multicusp plasma generator with RF antenna

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yasuo; Hanada, Masaya; Okumura, Yoshikazu; Tanaka, Masanobu [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1992-10-01

    A high density plasma was produced by radio-frequency in a multicusp plasma generator. The generator is a cylindrical chamber of 200 mm in inner diameter and 270 mm in length with 1-3 turn copper tube antenna. By injecting a 2 MHz, 20 kW RF into the multicusp plasma generator, hydrogen plasma of an ion saturation current density of 120 mA/cm{sup 2} and a hydrogen plasma of a density of 6.0 x 10{sup 11} cm{sup -3} was produced at a pressure of 0.6 Pa in the generator. The ion saturation current density was uniform over the central area of 100 mm in diameter. Coating the antenna with an insulator, we proved that the efficiency of the plasma production was improved. (author).

  9. High density plasma production in a multicusp plasma generator with RF antenna

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yasuo; Hanada, Masaya; Okumura, Yoshikazu; Tanaka, Masanobu (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment)

    1992-10-01

    A high density plasma was produced by radio-frequency in a multicusp plasma generator. The generator is a cylindrical chamber of 200 mm in inner diameter and 270 mm in length with 1-3 turn copper tube antenna. By injecting a 2 MHz, 20 kW RF into the multicusp plasma generator, hydrogen plasma of an ion saturation current density of 120 mA/cm[sup 2] and a hydrogen plasma of a density of 6.0 x 10[sup 11] cm[sup -3] was produced at a pressure of 0.6 Pa in the generator. The ion saturation current density was uniform over the central area of 100 mm in diameter. Coating the antenna with an insulator, we proved that the efficiency of the plasma production was improved. (author).

  10. Slot-Antenna/Permanent-Magnet Device for Generating Plasma

    Science.gov (United States)

    Foster, John E.

    2007-01-01

    A device that includes a rectangular-waveguide/slot-antenna structure and permanent magnets has been devised as a means of generating a substantially uniform plasma over a relatively large area, using relatively low input power and a low gas flow rate. The device utilizes electron cyclotron resonance (ECR) excited by microwave power to efficiently generate plasma in a manner that is completely electrodeless in the sense that, in principle, there is no electrical contact between the plasma and the antenna. Plasmas generated by devices like this one are suitable for use as sources of ions and/or electrons for diverse material-processing applications (e.g., etching or deposition) and for ion thrusters. The absence of plasma/electrode contact essentially prevents plasma-induced erosion of the antenna, thereby also helping to minimize contamination of the plasma and of objects exposed to the plasma. Consequently, the operational lifetime of the rectangular-waveguide/ slot-antenna structure is long and the lifetime of the plasma source is limited by the lifetime of the associated charged-particle-extraction grid (if used) or the lifetime of the microwave power source. The device includes a series of matched radiating slot pairs that are distributed along the length of a plasma-source discharge chamber (see figure). This arrangement enables the production of plasma in a distributed fashion, thereby giving rise to a uniform plasma profile. A uniform plasma profile is necessary for uniformity in any electron- or ion-extraction electrostatic optics. The slotted configuration of the waveguide/ antenna structure makes the device scalable to larger areas and higher powers. All that is needed for scaling up is the attachment of additional matched radiating slots along the length of the discharge chamber. If it is desired to make the power per slot remain constant in scaling up, then the input microwave power must be increased accordingly. Unlike in prior ECR microwave plasma-generating

  11. Gap Junction-Mediated Signaling from Motor Neurons Regulates Motor Generation in the Central Circuits of Larval Drosophila.

    Science.gov (United States)

    Matsunaga, Teruyuki; Kohsaka, Hiroshi; Nose, Akinao

    2017-02-22

    In this study, we used the peristaltic crawling of Drosophila larvae as a model to study how motor patterns are regulated by central circuits. We built an experimental system that allows simultaneous application of optogenetics and calcium imaging to the isolated ventral nerve cord (VNC). We then investigated the effects of manipulating local activity of motor neurons (MNs) on fictive locomotion observed as waves of MN activity propagating along neuromeres. Optical inhibition of MNs with halorhodopsin3 in a middle segment (A4, A5, or A6), but not other segments, dramatically decreased the frequency of the motor waves. Conversely, local activation of MNs with channelrhodopsin2 in a posterior segment (A6 or A7) increased the frequency of the motor waves. Since peripheral nerves mediating sensory feedback were severed in the VNC preparation, these results indicate that MNs send signals to the central circuits to regulate motor pattern generation. Our results also indicate segmental specificity in the roles of MNs in motor control. The effects of the local MN activity manipulation were lost in shaking-B(2) (shakB(2) ) or ogre(2) , gap-junction mutations in Drosophila, or upon acute application of the gap junction blocker carbenoxolone, implicating electrical synapses in the signaling from MNs. Cell-type-specific RNAi suggested shakB and ogre function in MNs and interneurons, respectively, during the signaling. Our results not only reveal an unexpected role for MNs in motor pattern regulation, but also introduce a powerful experimental system that enables examination of the input-output relationship among the component neurons in this system.SIGNIFICANCE STATEMENT Motor neurons are generally considered passive players in motor pattern generation, simply relaying information from upstream interneuronal circuits to the target muscles. This study shows instead that MNs play active roles in the control of motor generation by conveying information via gap junctions to the

  12. Ultra-High Intensity Magnetic Field Generation in Dense Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, Nathaniel J. [Princeton Univ., NJ (United States)

    2014-01-08

    The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereas the efficient generation of electric current in low-­energy-­density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­energy-­density plasma the ideas for steady-­state current drive developed for low-­energy-­density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­energy-­density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

  13. Ultra-High Intensity Magnetic Field Generation in Dense Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, Nathaniel J

    2014-01-08

    I. Grant Objective The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereasthefficient generation of electric current in low-­energy-­density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­energy-­density plasma the ideas for steady-­state current drive developed for low-­energy-­density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­energy-­density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

  14. Co-Simulation of BLDC Motor Commutation by using MATLAB Simulink and Xilinx System generator

    Directory of Open Access Journals (Sweden)

    Suneeta

    2016-04-01

    Full Text Available This work mainly focuses on Matlab Simulink model for electronic commutation of BLDC motor and co simulation of the model by using Xilinx System generator tool. The BLDC motors (AKM21E are available in small size with good speed/torque characteristics. Since, the efficiency and dynamic response is high compared to brushed DC motor, they have widely used in various applications. We are using BLDC motor for adjusting the focus in radio telescope. The efficient electronic commutation is designed and tested by using modelling in Matlab Simulink. The Co verification of the model is done by using Xilinx system generator.

  15. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander [Institute of Experimental Physics, University of Hamburg, 22761 Hamburg (Germany); Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B. [Particle Beam Physics Laboratory, UCLA, Los Angeles, CA 90095 (United States); Bruhwiler, David L. [RadiaSoft LLC, Boulder, CO 80304 (United States); RadiaBeam Technologies LLC (United States); Smith, Jonathan [Tech-X UK Ltd, Daresbury, Cheshire WA4 4FS (United Kingdom); Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G. [Physics Department, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Hidding, Bernhard [Institute of Experimental Physics, University of Hamburg, 22761 Hamburg (Germany); Physics Department, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical “plasma torch” distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  16. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    Science.gov (United States)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B.; Bruhwiler, David L.; Smith, Jonathan; Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G.; Hidding, Bernhard

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical "plasma torch" distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  17. The Dynamical Generation of Current Sheets in Astrophysical Plasma Turbulence

    CERN Document Server

    Howes, Gregory G

    2016-01-01

    Turbulence profoundly affects particle transport and plasma heating in many astrophysical plasma environments, from galaxy clusters to the solar corona and solar wind to Earth's magnetosphere. Both fluid and kinetic simulations of plasma turbulence ubiquitously generate coherent structures, in the form of current sheets, at small scales, and the locations of these current sheets appear to be associated with enhanced rates of dissipation of the turbulent energy. Therefore, illuminating the origin and nature of these current sheets is critical to identifying the dominant physical mechanisms of dissipation, a primary aim at the forefront of plasma turbulence research. Here we present evidence from nonlinear gyrokinetic simulations that strong nonlinear interactions between counterpropagating Alfven waves, or strong Alfven wave collisions, are a natural mechanism for the generation of current sheets in plasma turbulence. Furthermore, we conceptually explain this current sheet development in terms of the nonlinear...

  18. Reduced plasma taurine level in Parkinson's disease: association with motor severity and levodopa treatment.

    Science.gov (United States)

    Zhang, Li; Yuan, Yongsheng; Tong, Qing; Jiang, Siming; Xu, Qinrong; Ding, Jian; Zhang, Lian; Zhang, Rui; Zhang, Kezhong

    2016-01-01

    This study aimed to evaluate the level of taurine in plasma, and its association with the severity of motor and non-motor symptoms (NMS) and chronic levodopa treatment in Parkinson's disease (PD). Plasma taurine level was measured in treated PD (tPD), untreated PD (ntPD) and control groups. Motor symptoms and NMS were assessed using the Unified Parkinson's Disease Rating Scale, the short form of the McGill Pain Questionnaire, the Hamilton Depression Scale, the Scale for Outcomes in Parkinson's disease for Autonomic Symptoms and the Pittsburgh Sleep Quality Index. Longtime exposure to levodopa was indicated by its approximate cumulative dosage. The plasma taurine levels of PD patients were decreased when compared with controls and negatively associated with motor severity but not NMS. Moreover, tPD patients exhibited lower levels of plasma taurine than ntPD patients. Interestingly, plasma taurine levels negatively correlated with cumulative levodopa dosage in tPD. After controlling for potential confounders, the association between taurine and levodopa remained significant. Our study supports that taurine may play important roles in the pathophysiology of PD and the disturbances caused by chronic levodopa administration.

  19. Plasma erosion switches with imploding plasma loads on the pithon generator

    Science.gov (United States)

    Stringfield, R.; Schneider, R.; Genuario, R. D.; Roth, I.; Childers, K.; Stallings, C.; Dakin, D.

    1981-03-01

    Plasma erosion switches have been fielded on the PITHON generator during imploding plasma experiments. Theta pinch plasma guns were used to inject carbon plasmas of densities in the range 10 12-10 14/cm 3 between the electrodes of the vacuum power feed region, upstream from an imploding plasma load. Current monitors indicated that the erosion switches carried substantial current early in time, diverting it from the load. Late in the pulse the erosion switches opened, transferring the current to an imploding plasma with the effect of sharpening the current risetime at the load. Associated with the sharper risetime was an improvement in the quality of the plasma implosions. The results of varying the density and total number of particles in the plasma of the switches are presented with regard to the effect on the current along the vacuum feed and on the behavior of vacuum flowing electrons.

  20. Plasma erosion switches with imploding plasma loads on a multiterawatt pulsed power generator

    Science.gov (United States)

    Stringfield, R.; Schneider, R.; Genuario, R. D.; Roth, I.; Childers, K.; Stallings, C.; Dakin, D.

    1981-03-01

    Plasma erosion switches have been fielded on the PITHON generator during imploding plasma experiments. Theta pinch plasma guns were used to inject carbon plasmas of densities in the range of 10 to the 12th to 10 to the 14th/cu cm between the electrodes of the vacuum power feed region, upstream from an imploding plasma load. Current monitors indicated that the erosion switches carried substantial current early in time, diverting it from the load. Late in the pulse the erosion switches opened, transferring the current to an imploding plasma with the effect of sharpening the current rise time at the load. Associated with the sharper rise time was an improvement in the quality of the plasma implosions. The results of varying the density and total number of particles in the plasma of the switches are presented with regard to the effect on the current along the vacuum feed and on the behavior of vacuum flowing electrons.

  1. A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yang Min; Li Xiaoping; Xie Kai; Liu Donglin [School of Electronical and Mechanical Engineering, Xidian University, Xi' an Shaanxi 710071 (China); Liu Yanming [School of Telecommunications Engineering, Xidian University, Xi' an Shaanxi 710071 (China)

    2013-01-15

    A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a 'black out' phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm Multiplication-Sign 260 mm Multiplication-Sign 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.

  2. Carbon Multicharged Ion Generation from Laser Plasma

    Science.gov (United States)

    Balki, Oguzhan; Elsayed-Ali, Hani E.

    2014-10-01

    Multicharged ions (MCI) have potential uses in different areas such as microelectronics and medical physics. Carbon MCI therapy for cancer treatment is considered due to its localized energy delivery to hard-to-reach tumors at a minimal damage to surrounding tissues. We use a Q-switched Nd:YAG laser with 40 ns pulse width operated at 1064 nm to ablate a graphite target in ultrahigh vacuum. A time-of-flight energy analyzer followed by a Faraday cup is used to characterize the carbon MCI extracted from the laser plasma. The MCI charge state and energy distribution are obtained. With increase in the laser fluence, the ion charge states and ion energy are increased. Carbon MCI up to C+6 are observed along with carbon clusters. When an acceleration voltage is applied between the carbon target and a grounded mesh, ion extraction is observed to increase with the applied voltage. National Science Foundation.

  3. On the generation of magnetic field enhanced microwave plasma line

    Science.gov (United States)

    Chen, Longwei; Zhao, Ying; Wu, Kenan; Wang, Qi; Meng, Yuedong; Ren, Zhaoxing

    2016-12-01

    Microwave linear plasmas sustained by surface waves have attracted much attention due to the potential abilities to generate large-scale and uniform non-equilibrium plasmas. An external magnetic field was generally applied to enhance and stabilize plasma sources because the magnetic field decreased the electron losses on the wall. The effects of magnetic field on the generation and propagation mechanisms of the microwave plasma were tentatively investigated based on a 2-D numerical model combining a coupled system of Maxwell's equations and continuity equations. The mobility of electrons and effective electric conductivity of the plasma were considered as a full tensor in the presence of magnetic field. Numerical results indicate that both cases of magnetic field in the axial-direction and radial-direction benefit the generation of a high-density plasma; the former one allows the microwave to propagate longer in the axis direction compared to the latter one. The time-averaged power flow density and the amplitude of the electric field on the inner rod of coaxial waveguide attenuate with the propagation of the microwave for both cases of with and without external magnetic field. The attenuation becomes smaller in the presence of appropriately higher axial-direction magnetic field, which allows more microwave energies to transmit along the axial direction. Meanwhile, the anisotropic properties of the plasma, like electron mobility, in the presence of the magnetic field confine more charged particles in the direction of the magnetic field line.

  4. Characterization of inductively coupled plasma generated by a quadruple antenna

    Science.gov (United States)

    Shafir, G.; Zolotukhin, D.; Godyak, V.; Shlapakovski, A.; Gleizer, S.; Slutsker, Ya; Gad, R.; Bernshtam, V.; Ralchenko, Yu; Krasik, Ya E.

    2017-02-01

    The results of the characterization of large-scale RF plasma for studying nonlinear interaction with a high-power (˜400 MW) short duration (˜0.8 ns) microwave (˜10 GHz) beam are presented. The plasma was generated inside a Pyrex tube 80 cm in length and 25 cm in diameter filled by either Ar or He gas at a pressure in the range 1.3-13 Pa using a 2 MHz RF generator with a matching system and a quadruple antenna. Good matching was obtained between the plasma parameters, which were determined using different methods including a movable Langmuir probe, microwave cut-off, interferometry, and optical emission spectroscopy. It was shown that, depending on the gas pressure and RF power delivered to the antenna, the plasma density and electron temperature can be controlled in the range 1 × 1010-5 × 1012 cm-3 and 1-3.5 eV, respectively. The plasma density was found to be uniform in terms of axial (˜60 cm) and radial (˜10 cm) dimensions. Further, it was also shown that the application of the quadruple antenna, with resonating capacitors inserted in its arms, decreases the capacitive coupling of the antenna and the plasma as well as the RF power loss along the antenna. These features make this plasma source suitable for microwave plasma wake field experiments.

  5. Laser-generated plasma by carbon nanoparticles embedded into polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L., E-mail: lorenzo.torrisi@unime.it [Dipartimento di Scienze Fisiche MIFT, Università di Messina, V.le F.S. D’Alcontres 31, 98166 S. Agata, Messina (Italy); Ceccio, G. [Dipartimento di Scienze Fisiche MIFT, Università di Messina, V.le F.S. D’Alcontres 31, 98166 S. Agata, Messina (Italy); Cutroneo, M. [Nuclear Physics Institute, AS CR, 25068 Rez (Czech Republic)

    2016-05-15

    Highlights: • Advanced targets are prepared using UHMWPE containing CNT at different concentrations. • The composite has different optical, mechanical, electrical and compositional properties with respect to polyethylene. • Higher ion accelerations with respect to the pure polyethylene are obtained from laser generated plasmas at 10{sup 10} W/cm{sup 2} intensity. • High carbon ion yields with respect to the pure polyethylene are obtained from laser generated plasmas at 10{sup 10} W/cm{sup 2} intensity. • Advanced targets were prepared to be irradiated in TNSA regime using laser at 10{sup 18} W/cm{sup 2} intensity. - Abstract: Carbon nanoparticles have been embedded into polyethylene at different concentrations by using chemical–physical processes. The synthesized material was characterized in terms of physical modifications concerning the mechanical, compositional and optical properties. Obtained flat targets have been irradiated by Nd:YAG laser at intensities of the order of 10{sup 10} W/cm{sup 2} in order to generate non-equilibrium plasma in vacuum. The laser–matter interaction produces charge separation effects with consequent acceleration of protons and carbon ions. Plasma was characterized using time-of-flight measurements of the accelerated ions. Applications of the produced targets in order to generate carbon ion beams from laser-generated plasma are presented and discussed.

  6. Study of parameters of a facility generating compressive plasma flows

    Science.gov (United States)

    Leyvi, A. Ya

    2017-05-01

    The prosperity of plasma technologies stimulates making of a facility generating compressive plasma flows at the South Ural State University. The facility is a compact-geometry magnetoplasma compressor with the following parameters: stored energy up to 15 kJ, voltage of a bank from 3 to 5 kV; nitrogen, air, and other gases can serve as its operating gas. The investigation of parameters of the facility showed the following parameters of compressive plasma flows: impulse duration of up to 120 μs, discharge current of 50-120 kA, speed of plasma flow of 15-30 km/s. By contrast to the available facilities, the parameters of the developed facility can be adjusted in a wide range of voltage from 2 kV to 10 kV, its design permits generating CPF in horizontal and vertical positions.

  7. Electrode assemblies, plasma apparatuses and systems including electrode assemblies, and methods for generating plasma

    Science.gov (United States)

    Kong, Peter C; Grandy, Jon D; Detering, Brent A; Zuck, Larry D

    2013-09-17

    Electrode assemblies for plasma reactors include a structure or device for constraining an arc endpoint to a selected area or region on an electrode. In some embodiments, the structure or device may comprise one or more insulating members covering a portion of an electrode. In additional embodiments, the structure or device may provide a magnetic field configured to control a location of an arc endpoint on the electrode. Plasma generating modules, apparatus, and systems include such electrode assemblies. Methods for generating a plasma include covering at least a portion of a surface of an electrode with an electrically insulating member to constrain a location of an arc endpoint on the electrode. Additional methods for generating a plasma include generating a magnetic field to constrain a location of an arc endpoint on an electrode.

  8. Generation of Diffuse Large Volume Plasma by an Ionization Wave from a Plasma Jet

    Science.gov (United States)

    Laroussi, Mounir; Razavi, Hamid

    2015-09-01

    Low temperature plasma jets emitted in ambient air are the product of fast ionization waves that are guided within a channel of a gas flow, such as helium. This guided ionization wave can be transmitted through a dielectric material and under some conditions can ignite a discharge behind the dielectric material. Here we present a novel way to produce large volume diffuse low pressure plasma inside a Pyrex chamber that does not have any electrodes or electrical energy directly applied to it. The diffuse plasma is ignited inside the chamber by a plasma jet located externally to the chamber and that is physically and electrically unconnected to the chamber. Instead, the plasma jet is just brought in close proximity to the external wall/surface of the chamber or to a dielectric tubing connected to the chamber. The plasma thus generated is diffuse, large volume and with physical and chemical characteristics that are different than the external plasma jet that ignited it. So by using a plasma jet we are able to ``remotely'' ignite volumetric plasma under controlled conditions. This novel method of ``remote'' generation of a low pressure, low temperature diffuse plasma can be useful for various applications including material processing and biomedicine.

  9. Generation of auroral kilometric radiation in inhomogeneous magnetospheric plasma

    Science.gov (United States)

    Burinskaya, T. M.; Shevelev, M. M.

    2017-01-01

    The generation of auroral kilometric radiation in a narrow 3D plasma cavity, in which a weakly relativistic electron flow is propagated along the magnetic field against a low-density cold background plasma, is studied. The time dynamics of the propagation and intensification of waves are analyzed using geometric optics equations. The waves have different wave vector components and start from the cavity center at an altitude of about the Earth's radius at plasma parameters typical for the auroral zone at this altitude. It is shown that the global inhomogeneity of the Earth's magnetic field is of key importance in shaping the auroral kilometric radiation spectra.

  10. Sufficient conditions for the additivity of stall forces generated by multiple filaments or motors

    Science.gov (United States)

    Bameta, Tripti; Das, Dipjyoti; Das, Dibyendu; Padinhateeri, Ranjith; Inamdar, Mandar M.

    2017-02-01

    Molecular motors and cytoskeletal filaments work collectively most of the time under opposing forces. This opposing force may be due to cargo carried by motors or resistance coming from the cell membrane pressing against the cytoskeletal filaments. Some recent studies have shown that the collective maximum force (stall force) generated by multiple cytoskeletal filaments or molecular motors may not always be just a simple sum of the stall forces of the individual filaments or motors. To understand this excess or deficit in the collective force, we study a broad class of models of both cytoskeletal filaments and molecular motors. We argue that the stall force generated by a group of filaments or motors is additive, that is, the stall force of N number of filaments (motors) is N times the stall force of one filament (motor), when the system is reversible at stall. Conversely, we show that this additive property typically does not hold true when the system is irreversible at stall. We thus present a novel and unified understanding of the existing models exhibiting such non-addivity, and generalise our arguments by developing new models that demonstrate this phenomena. We also propose a quantity similar to thermodynamic efficiency to easily predict this deviation from stall-force additivity for filament and motor collectives.

  11. Laser-generated plasma by carbon nanoparticles embedded into polyethylene

    Science.gov (United States)

    Torrisi, L.; Ceccio, G.; Cutroneo, M.

    2016-05-01

    Carbon nanoparticles have been embedded into polyethylene at different concentrations by using chemical-physical processes. The synthesized material was characterized in terms of physical modifications concerning the mechanical, compositional and optical properties. Obtained flat targets have been irradiated by Nd:YAG laser at intensities of the order of 1010 W/cm2 in order to generate non-equilibrium plasma in vacuum. The laser-matter interaction produces charge separation effects with consequent acceleration of protons and carbon ions. Plasma was characterized using time-of-flight measurements of the accelerated ions. Applications of the produced targets in order to generate carbon ion beams from laser-generated plasma are presented and discussed.

  12. Generation of low-temperature air plasma for food processing

    Science.gov (United States)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  13. Unbalance Response Analysis and Experimental Validation of an Ultra High Speed Motor-Generator for Microturbine Generators Considering Balancing

    Directory of Open Access Journals (Sweden)

    Do-Kwan Hong

    2014-08-01

    Full Text Available The objective of the present study was to deal with the rotordynamics of the rotor of an ultra-high speed PM type synchronous motor-generator for a 500 W rated micro gas turbine generator. This paper introduces dynamic analysis, and experiments on the motor-generator. The focus is placed on an analytical approach considering the mechanical dynamic problems. It is essential to deal with dynamic stability at ultra-high speeds. Unbalance response analysis is performed by calculating the unbalance with and without balancing using a balancing machine. Critical speed analysis is performed to determine the operating speed with sufficient separation margin. The unbalance response analysis is compared with the experimental results considering the balancing grade (ISO 1940-1 and predicted vibration displacement with and without balancing. Based on these results, a high-speed motor-generator was successfully developed.

  14. Unbalance response analysis and experimental validation of an ultra high speed motor-generator for microturbine generators considering balancing.

    Science.gov (United States)

    Hong, Do-Kwan; Joo, Dae-Suk; Woo, Byung-Chul; Koo, Dae-Hyun; Ahn, Chan-Woo

    2014-08-29

    The objective of the present study was to deal with the rotordynamics of the rotor of an ultra-high speed PM type synchronous motor-generator for a 500 W rated micro gas turbine generator. This paper introduces dynamic analysis, and experiments on the motor-generator. The focus is placed on an analytical approach considering the mechanical dynamic problems. It is essential to deal with dynamic stability at ultra-high speeds. Unbalance response analysis is performed by calculating the unbalance with and without balancing using a balancing machine. Critical speed analysis is performed to determine the operating speed with sufficient separation margin. The unbalance response analysis is compared with the experimental results considering the balancing grade (ISO 1940-1) and predicted vibration displacement with and without balancing. Based on these results, a high-speed motor-generator was successfully developed.

  15. Development of a high-efficiency motor/generator for flywheel energy storage

    Science.gov (United States)

    Lashley, Christopher; Anand, Dave K.; Kirk, James A.; Zmood, Ronald B.

    1991-01-01

    This study addresses the design changes and extensions necessary to construct and test a working prototype of a motor/generator for a magnetically suspended flywheel energy storage system. The brushless motor controller for the motor was specified and the electronic commutation arrangement designed. The laminations were redesigned and fabricated using laser machining. Flux density measurements were made and the results used to redesign the armature windings. A test rig was designed and built, and the motor/generator was installed and speed tested to 9000 rpm. Experimental methods of obtaining the machine voltage and torque constants Kv and Kt, obtaining the useful air-gap flux density, and characterizing the motor and other system components are described. The measured Kv and Kt were approximately 40 percent greater than predicted by theory and initial experiment.

  16. Analyses of the plasma generated by laser irradiation on sputtered target for determination of the thickness used for plasma generation

    Energy Technology Data Exchange (ETDEWEB)

    Kumaki, Masafumi, E-mail: masafumi.kumaki@riken.jp [Cooperative Major in Nuclear Energy, Waseda University, Shinjuku, Tokyo (Japan); RIKEN, Wako, Saitama (Japan); Ikeda, Shunsuke; Sekine, Megumi; Munemoto, Naoya [RIKEN, Wako, Saitama (Japan); Department of Energy Sciences, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Fuwa, Yasuhiro [RIKEN, Wako, Saitama (Japan); Department of Physics and Astronomy, Kyoto University, Uji, Kyoto (Japan); Cinquegrani, David [American Nuclear Society, University of Michigan, Ann Arbor, Michigan 48109 (United States); Kanesue, Takeshi; Okamura, Masahiro [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Washio, Masakazu [Cooperative Major in Nuclear Energy, Waseda University, Shinjuku, Tokyo (Japan)

    2014-02-15

    In Brookhaven National Laboratory, laser ion source has been developed to provide heavy ion beams by using plasma generation with 1064 nm Nd:YAG laser irradiation onto solid targets. The laser energy is transferred to the target material and creates a crater on the surface. However, only the partial material can be turned into plasma state and the other portion is considered to be just vaporized. Since heat propagation in the target material requires more than typical laser irradiation period, which is typically several ns, only the certain depth of the layers may contribute to form the plasma. As a result, the depth is more than 500 nm because the base material Al ions were detected. On the other hand, the result of comparing each carbon thickness case suggests that the surface carbon layer is not contributed to generate plasma.

  17. Interstellar Turbulent Magnetic Field Generation by Plasma Instabilities

    CERN Document Server

    Tautz, R C

    2013-01-01

    The maximum magnetic field strength generated by Weibel-type plasma instabilities is estimated for typical conditions in the interstellar medium. The relevant kinetic dispersion relations are evaluated by conducting a parameter study both for Maxwellian and for suprathermal particle distributions showing that micro Gauss magnetic fields can be generated. It is shown that, depending on the streaming velocity and the plasma temperatures, either the longitudinal or a transverse instability will be dominant. In the presence of an ambient magnetic field, the filamentation instability is typically suppressed while the two-stream and the classic Weibel instability are retained.

  18. Overdense plasma generation in a compact ion source

    Science.gov (United States)

    Castro, G.; Mascali, D.; Gammino, S.; Torrisi, G.; Romano, F. P.; Celona, L.; Altana, C.; Caliri, C.; Gambino, N.; Lanaia, D.; Miracoli, R.; Neri, L.; Sorbello, G.

    2017-05-01

    Electron cyclotron resonance ion sources (ECRIS) are widely used plasma based machines for the production of intense ion beams in science and industry. The performance of modern devices is limited by the presence of the density cut-off, above which electromagnetic (EM) waves sustaining the plasma are reflected. We hereby discuss the systematic data analysis of electrostatic wave generation in an ECR prototype operating at 3.75 GHz-0.1 THz. In particular, electron Bernstein waves (EBW) have been excited. EBW have already been generated in large-scale plasma devices for thermonuclear fusion purposes. In ion sources where L c ˜ λ RF (L c being the plasma chamber size and λ RF the pumping wave wavelength) the EM field assumes a modal behaviour; thus both plasma and EM field self-organize so that no optical-like wave launching is possible (i.e. the cavity effect dominates on the optical path). The collected data, however, supported by 3D full-wave simulations, actually demonstrate that a Budden-type X-B conversion scenario can be established above some critical RF power thresholds, operating in an off-ECR regime. The generation and absorption of the EBW has been demonstrated by the presence of three peculiar signatures: along with the establishment of an overdense plasma, generation of supra-thermal electrons and modification (non-linear broadening) of the EM spectrum measured within the plasma have been observed. At the threshold establishing such a heating regime, the collected data provide evidence for a fast rotation of the electron fluid.

  19. Relationship between the plasma levels of neurodegenerative proteins and motor subtypes of Parkinson's disease.

    Science.gov (United States)

    Ding, Jian; Zhang, Jiejin; Wang, Xixi; Zhang, Li; Jiang, Siming; Yuan, Yongsheng; Li, Junyi; Zhu, Lin; Zhang, Kezhong

    2017-03-01

    The aim of our study is to examine the plasma levels of the four kinds of neurodegenerative proteins in plasma: α-syn, T-tau, P-tau181, and Aβ-42 in Parkinson's disease (PD) and to evaluate the relationship between their plasma levels and PD motor subtypes. 84 patients with PD were enrolled in our study, and finally, 73 of them were classified into the tremor-dominant subtype (TD) and the postural instability gait difficulty subtype (PIGD). Their motor performance was evaluated by a series of clinical assessments: Freezing of Gait Questionnaire (FOGQ), Timed Up and Go (TUGs), Tinetti balance, and Tinetti gait. Plasma levels of these proteins were measured by enzyme-linked immunosorbent assay (ELISA). The plasma level of α-syn was significantly higher in PD patients when compared to controls (p = 0.004), and significantly higher in the PIGD group when compared to the TD group (p = 0.03). While the plasma level of Aβ-42 was significantly lower in PD patients than in controls (p = 0.002), and significantly lower in the PIGD group than in the TD group (p = 0.05). In PD patients, the plasma level of α-syn (r = -0.355, p score, even after performing multiple linear regression (p = 0.002). While the plasma level of Aβ-42 (r = -0.261, p score and remained correlate when performed multiple linear regression (p = 0.005). The patients with PIGD subtype are characterized with a lower level of plasma Aβ-42 and a higher plasma level of α-syn, which may be used as biomarkers for diagnosis and progression of the subtypes of PD.

  20. Plasma effect on the phase matching of high harmonic generation

    Institute of Scientific and Technical Information of China (English)

    Hui Lu; Candong Liu; Shitong Zhao; Peng Liu

    2011-01-01

    By optimizing the phase matching condition of high harmonic generation (HHG) from a supersonic neon gas jet, the enhanced HHG in the region of 60-70 eV has been selected. Three-dimensional numerical calculation shows that plasma plays a significant role in the phase matching process of HHG in a supersonic gas jet with short medium length. Due to plasma formation, the harmonic emission decays as the laser intensity reaches over 3.5 × 1014 W/cm2. The plasma induces the broadening and blue shift of the HHG spectra, which provides a method for fine-tuning the harmonic wavelength.%@@ By optimizing the phase matching condition of high harmonic generation (HHG) from a supersonic neon gas jet, the enhanced HHG in the region of 60-70 eV has been selected. Three-dimensional numerical calculation shows that plasma plays a significant role in the phase matching process of HHG in a supersonic gas jet with short medium length. Due to plasma formation, the harmonic emission decays as the laser intensity reaches over 3.5 × 1014 W/cm2. The plasma induces the broadening and blue shift of the HHG spectra, which provides a method for fine-tuning the harmonic wavelength.

  1. Opacity measurements in shock-generated argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.

    1993-07-01

    Dense plasmas having uniform and constant density and temperature are generated by passage of a planar shock wave through gas. The opacity of the plasma is accurately measured versus wavelength by recording the risetime of emitted light. This technique is applicable to a wide variety of species and plasma conditions. Initial experiments in argon have produced plasmas with 2 eV temperatures, 0.004--0.04 g/cm{sup 3} densities, and coupling parameters {Gamma} {approximately}0.3--0.7. Measurements in visible light are compared with calculations using the HOPE code. An interesting peak in the capacity at 400 nm is observed for the first time and is identified with the 4s-5p transition in excited neutral argon atoms.

  2. The high flux plasma generator Magnum-PSI

    Science.gov (United States)

    van Eck, H. J. N.; Kleyn, A. W.; Koppers, W. R.; Rapp, J.; Zeijlmans van Emmichoven, P. A.

    2010-11-01

    Magnum-PSI is a magnetized (3 T), high-flux (up to 10^24 H^+ ions m-2s-1) plasma generator, capable of delivering 10 MW m-2 steady-state power fluxes to a large area target. Magnum-PSI is a highly accessible laboratory experiment in which the interaction of magnetized plasma with different surfaces can be studied. This experiment will provide new insights in the complex physics and chemistry that will occur in the divertor region of the future experimental fusion reactor ITER and reactors beyond ITER. In this contribution, we will present the design and characterization of the Magnum-PSI experiment. The differentially pumped vacuum system, the superconducting magnet, the plasma source, the target plate and manipulator will be presented. Simulations and measurements of the neutral gas flow, as well as electron density and temperature measurements of the plasma beam will be presented. Furthermore, a flavor of upcoming PSI experiments will be given.

  3. Generation of radiation by intense plasma and electromagnetic undulators

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, C.

    1991-10-01

    We examine the characteristics of the classical radiation emission resulting from the interaction of a relativistic electron beam that propagates perpendicularly through a large amplitude relativistic plasma wave. Such a study is useful for evaluating the feasibility of using relativistic plasma waves as extremely short wavelength undulators for generating short wavelength radiation. The electron trajectories in a plasma wave undulator and in an ac FEL undulator are obtained using perturbation techniques. The spontaneous radiation frequency spectrum and angular distribution emitted by a single electron oscillating in these two undulators are then calculated. The radiation gain of a copropagating electromagnetic wave is calculated. The approximate analytic results for the trajectories, spontaneous radiation and gain are compared with 3-D simulation results. The characteristics of the plasma wave undulator are compared with the ac FEL undulator and linearly polarized magnetic undulator. 50 refs., 26 figs., 3 tabs.

  4. Secondary electron emission from plasma-generated nanostructured tungsten fuzz

    Science.gov (United States)

    Patino, M.; Raitses, Y.; Wirz, R.

    2016-11-01

    Recently, several researchers [e.g., Yang et al., Sci. Rep. 5, 10959 (2015)] have shown that tungsten fuzz can grow on a hot tungsten surface under bombardment by energetic helium ions in different plasma discharges and applications, including magnetic fusion devices with plasma facing tungsten components. This work reports the direct measurements of the total effective secondary electron emission (SEE) from tungsten fuzz. Using dedicated material surface diagnostics and in-situ characterization, we find two important results: (1) SEE values for tungsten fuzz are 40%-63% lower than for smooth tungsten and (2) the SEE values for tungsten fuzz are independent of the angle of the incident electron. The reduction in SEE from tungsten fuzz is most pronounced at high incident angles, which has important implications for many plasma devices since in a negative-going sheath the potential structure leads to relatively high incident angles for the electrons at the plasma confining walls. Overall, low SEE will create a relatively higher sheath potential difference that reduces plasma electron energy loss to the confining wall. Thus, the presence or self-generation in a plasma of a low SEE surface such as tungsten fuzz can be desirable for improved performance of many plasma devices.

  5. Generation of nano roughness on fibrous materials by atmospheric plasma

    Science.gov (United States)

    Kulyk, I.; Scapinello, M.; Stefan, M.

    2012-12-01

    Atmospheric plasma technology finds novel applications in textile industry. It eliminates the usage of water and of hazard liquid chemicals, making production much more eco-friendly and economically convenient. Due to chemical effects of atmospheric plasma, it permits to optimize dyeing and laminating affinity of fabrics, as well as anti-microbial treatments. Other important applications such as increase of mechanical resistance of fiber sleeves and of yarns, anti-pilling properties of fabrics and anti-shrinking property of wool fabrics were studied in this work. These results could be attributed to the generation of nano roughness on fibers surface by atmospheric plasma. Nano roughness generation is extensively studied at different conditions. Alternative explanations for the important practical results on textile materials and discussed.

  6. Pre-Excitation Studies for Rubidium-Plasma Generation

    CERN Document Server

    Aladi, M; Barna, I.F.; Czitrovszky, Aladar; Djotyan, Gagik; Dombi, Peter; Dzsotjan, David; FöLdes, Istvan; Hamar, Gergo; Ignacz, Peter; Kedves, Miklos; Kerekes, Attila; Levai, Peter; Marton, Istvan; Nagy, Attila; Oszetzky, Daniel; Pocsai, Mihaly; Racz, Peter; Raczkevi, Bela; Szigeti, Janos; Sörlei, Zsuzsa; Szipöcs, Robert; Varga, Dezso; Varga-Umbrich, Karoly; Varro, Sandor; Vamos, Lenard; Vesztergombi, György

    2014-01-01

    The key element in the Proton-Driven-Plasma-Wake-Field-Accelerator (AWAKE) project is the generation of highly uniform plasma from Rubidium vapor. The standard way to achieve full ionization is to use high power laser which can assure the over-barrier-ionization (OBI) along the 10 meters long active region. The Wigner-team in Budapest is investigating an alternative way of uniform plasma generation. The proposed Resonance Enhanced Multi Photon Ionization (REMPI) scheme probably can be realized by much less laser power. In the following the resonant pre-excitations of the Rb atoms are investigated, theoretically and the status report about the preparatory work on the experiment are presented.

  7. Intense ion beam generation, plasma radiation source and plasma opening switch research

    Science.gov (United States)

    Hammer, D. A.; Coleman, M. D.; Qi, N.; Similon, P. L.; Sudan, R. N.

    1989-04-01

    This report describes research on intense ion beam diodes, plasma opening switches and dense z-pinch plasma radiators. Laser induced fluorescence spectroscopy has been used to map the electrostatic potential profile in a plasma-prefilled magnetically insulated ion diode. In a simple planar diode, the measured profile is inconsistent with the electrons being confined in a sheath near the cathode by the magnetic field. Rather, the profile implies the presence of electrons throughout the accelerating gap. A theoretical model of the penetration of current and magnetic field into a plasma, and of the current-driven effective collision frequency has been developed. The snowplow action of the rising magnetic field causes a steep rise in the plasma density at the leading edge. The subsequent multistreaming of the ions caused by ion reflection at the current layer could lead to ion heating through collective effects. The two-dimensional electron flow in the plasma cathode vacuum gap is also treated. Dense z-pinch plasma radiation source experiments have been initiated on the LION accelerator using gas puff and fine wire loads. The x-pinch was found to be a more effective way to generate soft x-rays than a single wire pinch or a gas puff implosion. Plasma opening switch experiments being initiated, and plasma anode ion diode development work being terminated are also briefly described.

  8. Application possibilities of plasmas generated by high power laser ablation

    OpenAIRE

    Torrisi, L.

    2009-01-01

    High-power pulsed lasers emitting IR and visible radiation with intensities ranging between 10^8 and 10^16 W/cm2, pulse duration from 0.4 to 9 ns and energy from 100 mJ up to 600 J, operating in single mode or in repetition rate, can be employed to produce non-equilibrium plasma in vacuum by irradiating solid targets. Such a laser-produced plasma generates highly charged and high-energy ions of various elements, as well as soft and hard X-ray radiations. Heavy ions with charge state up to 58+...

  9. Magnetohydrodynamic dynamo: global flow generation in plasma turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Yokoi, Nobumitsu; Yoshizawa, Akira [Tokyo Univ. (Japan). Inst. of Industrial Science; Itoh, Kimitaka; Itoh, Sanae-I.

    1999-07-01

    Generation mechanism of the spontaneous plasma rotation observed in an improved confinement mode in tokamak's is examined from the viewpoint of the turbulent magnetohydrodynamic (MHD) dynamo. A dynamo model, where the concept of cross helicity (velocity/magnetic-field correlation) plays a key role, is applied to the reversed shear (RS) modes. The concave electric-current profile occurred in the RS modes is shown to be a cause of the global plasma rotation through a numerical simulation of the cross-helicity turbulence model. (author)

  10. A novel, all-dielectric, microwave plasma generator towards development of plasma metamaterials

    Science.gov (United States)

    Cohick, Zane; Luo, Wei; Perini, Steven; Baker, Amanda; Wolfe, Douglas; Lanagan, Michael

    2016-11-01

    A proof of concept for a microwave microplasma generator that consists of a halved dielectric resonator is presented. The generator functions via leaking electric fields of the resonant modes — TE01δ and HEM12δ modes are explored. Computational results illustrate the electric fields, whereas the stability of resonance and coupling are studied experimentally. Finally, a working device is presented. This generator promises potentially wireless and low-loss operation. This device may find relevance in plasma metamaterials; each resonator may generate the plasma structures necessary to manipulate electromagnetic radiation. In particular, the all-dielectric nature of the generator will allow low-loss interaction with high-frequency (GHz–THz) waves.

  11. Design of motor induction 3-Phase from waste industry to generator for microhydro at isolated village

    Science.gov (United States)

    Rimbawati; Azis Hutasuhut, Abdul; Irsan Pasaribu, Faisal; Cholish; Muharnif

    2017-09-01

    There is an electric machine that can operate as a generator either single-phase or three-phase in almost every household and industry today. This electric engine cannot be labeled as a generator but can be functioned as a generator. The machine that is mentioned is “squirrel cage motors” or it is well-known as induction motor that can be found in water pumps, washing machines, fans, blowers and other industrial machines. The induction motor can be functioned as a generator when the rotational speed of the rotor is made larger than the speed of the rotary field. In this regard, this study aims to modify the remains of 3-phase induction motor to be a permanent generator. Data of research based conducted on the river flow of Rumah Sumbul Village, STM Hulu district of Deli Serdang. The method of this research is by changing rotor and stator winding on a 3 phase induction motor, so it can produce a generator with rotation speed of 500 rpm. Based on the research, it can be concluded that the output voltage generator has occurred a voltage drop 10% between before and after loading for Star circuit and 2% for Delta circuit.

  12. Advanced targets, diagnostics and applications of laser-generated plasmas

    Science.gov (United States)

    Torrisi, L.

    2015-04-01

    High-intensity sub-nanosecond-pulsed lasers irradiating thin targets in vacuum permit generation of electrons and ion acceleration and high photon yield emission in non-equilibrium plasmas. At intensities higher than 1015 W/cm2 thin foils can be irradiated in the target-normal sheath acceleration regime driving ion acceleration in the forward direction above 1 MeV per charge state. The distributions of emitted ions in terms of energy, charge state and angular emission are controlled by laser parameters, irradiation conditions, target geometry and composition. Advanced targets can be employed to increase the laser absorption in thin foils and to enhance the energy and the yield of the ion acceleration process. Semiconductor detectors, Thomson parabola spectrometer and streak camera can be employed as online plasma diagnostics to monitor the plasma parameters, shot by shot. Some applications in the field of the multiple ion implantation, hadrontherapy and nuclear physics are reported.

  13. Electromagnetic radiation generated by arcing in low density plasma

    Science.gov (United States)

    Vayner, Boris V.; Ferguson, Dale C.; Snyder, David B.; Doreswamy, C. V.

    1996-01-01

    An unavoidable step in the process of space exploration is to use high-power, very large spacecraft launched into Earth orbit. Obviously, the spacecraft will need powerful energy sources. Previous experience has shown that electrical discharges occur on the surfaces of a high-voltage array, and these discharges (arcs) are undesirable in many respects. Moreover, any high voltage conductor will interact with the surrounding plasma, and that interaction may result in electrical discharges between the conductor and plasma (or between two conductors with different potentials, for example, during docking and extravehicular activity). One very important aspect is the generation of electromagnetic radiation by arcing. To prevent the negative influence of electromagnetic noise on the operation of spacecraft systems, it seems necessary to determine the spectra and absolute levels of the radiation, and to determine limitations on the solar array bias voltage that depend on the parameters of LEO plasma and the technical requirements of the spacecraft equipment. This report describes the results of an experimental study and computer simulation of the electromagnetic radiation generated by arcing on spacecraft surfaces. A large set of high quality data was obtained during the Solar Array Module Plasma Interaction Experiment (SAMPIE, flight STS-62) and ground test. These data include the amplitudes of current, pulse forms, duration of each arc, and spectra of plasma waves. A theoretical explanation of the observed features is presented in this report too. The elaborated model allows us to determine the parameters of the electromagnetic noise for different frequency ranges, distances from the arcing site, and distinct kinds of plasma waves.

  14. Plasma-generated reactive oxygen species for biomedical applications

    Science.gov (United States)

    Sousa, J. S.; Hammer, M. U.; Winter, J.; Tresp, H.; Duennbier, M.; Iseni, S.; Martin, V.; Puech, V.; Weltmann, K. D.; Reuter, S.

    2012-10-01

    To get a better insight into the effects of reactive oxygen species (ROS) on cellular components, fundamental studies are essential to determine the nature and concentration of plasma-generated ROS, and the chemistry induced in biological liquids by those ROS. In this context, we have measured the absolute density of the main ROS created in three different atmospheric pressure plasma sources: two geometrically distinct RF-driven microplasma jets (μ-APPJ [1] and kinpen [2]), and an array of microcathode sustained discharges [3]. Optical diagnostics of the plasma volumes and effluent regions have been performed: UV absorption for O3 and IR emission for O2(a^1δ) [4]. High concentrations of both ROS have been obtained (10^14--10^17cm-3). The effect of different parameters, such as gas flows and mixtures and power coupled to the plasmas, has been studied. For plasma biomedicine, the determination of the reactive species present in plasma-treated liquids is of great importance. In this work, we focused on the measurement of the concentration of H2O2 and NOX radicals, generated in physiological solutions like NaCl and PBS.[4pt] [1] N. Knake et al., J. Phys. D: App. Phys. 41, 194006 (2008)[0pt] [2] K.D. Weltmann et al., Pure Appl. Chem. 82, 1223 (2010)[0pt] [3] J.S. Sousa et al., Appl. Phys. Lett. 97, 141502 (2010)[0pt] [4] J.S. Sousa et al., Appl. Phys. Lett. 93, 011502 (2008)

  15. Simulation of current generation in a 3-D plasma model

    Energy Technology Data Exchange (ETDEWEB)

    Tsung, F.S.; Dawson, J.M. [Univ. of California, Los Angeles, CA (United States)

    1996-12-31

    Two wires carrying current in the same direction will attract each other, and two wires carrying current in the opposite direction will repel each other. Now, consider a test charge in a plasma. If the test charge carries current parallel to the plasma, then it will be pulled toward the plasma core, and if the test charge carries current anti-parallel to the plasma, then it will be pushed to the edge. The electromagnetic coupling between the plasma and a test charge (i.e., the A{sub {parallel}} {circ} v{sub {parallel}} term in the test charge`s Hamiltonian) breaks the symmetry in the parallel direction, and gives rise to a diffusion coefficient which is dependent on the particle`s parallel velocity. This is the basis for the {open_quotes}preferential loss{close_quotes} mechanism described in the work by Nunan et al. In our previous 2+{1/2}D work, in both cylindrical and toroidal geometries, showed that if the plasma column is centrally fueled, then an initial current increases steadily. The results in straight, cylindrical plasmas showed that self generated parallel current arises without trapped particle or neoclassical diffusion, as assumed by the bootstrap theory. It suggests that the fundamental mechanism seems to be the conservation of particles canonical momenta in the direction of the ignorable coordinate. We have extended the simulation to 3D to verify the model put forth. A scalable 3D EM-PIC code, with a localized field-solver, has been implemented to run on a large class of parallel computers. On the 512-node SP2 at Cornell Theory Center, we have benchmarked the 2+{1/2}D calculations using 32 grids in the previously ignored direction, and a 100-fold increase in the number of particles. Our preliminary results show good agreements between the 2+{1/2}D and the 3D calculations. We will present our 3D results at the meeting.

  16. Neutron Generation and Kinetic Energy of Expanding Laser Plasmas

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-Sheng; WANG Nai-Yan; DUAN Xiao-Jiao; LAN Xiao-Fei; TAN Zhi-Xin; TANG Xiu-Zhang; HE Ye-Xi

    2007-01-01

    We investigate the kinetic energy of expanding plasma of a solid target heated by a ultra-short and ultra-intense laser pulse and the efficiency of energy coupling between the ultra-intense laser pulse and the solid target, in order to increase the utilization ratio of laser energy and to raise the neutron generation farther. Some new ideas about improving the energy utilization by head-on collisions between the expanding plasmas are proposed. The significance is the raise of generation of shorter duration neutron, of the order of picoseconds, which allows for an increase of energy resolution in time-of-flight experiments and also for the investigation of the dynamics of nuclear processes with high temporal resolution.

  17. Propagation of Plasma Generated by Intense Pulsed Ion Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    WU Di; GONG Ye; LIU Jin-Yuan; WANG Xiao-Gang; LIU Yue; MA Teng-Cai

    2006-01-01

    @@ Taking the calculation results based on the established two-dimensional ablation model of the intense-pulsed-ion-beam (IPIB) irradiation process as initial conditions, we build a two-dimensional hydrodynamic ejection model of plasma produced by an IPIB-irradiated metal titanium target into ambient gas. We obtain the conclusions that shock waves generate when the background pressure is around 133 mTorr and also obtain the plume splitting phenomenon that has been observed in the experiments.

  18. Flowing dusty plasma experiments: generation of flow and measurement techniques

    Science.gov (United States)

    Jaiswal, S.; Bandyopadhyay, P.; Sen, A.

    2016-12-01

    A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a \\Pi -shaped dusty plasma experimental device with micron size kaolin/melamine formaldehyde particles embedded in a background of argon plasma created by a direct current glow discharge. A stationary dust cloud is formed over the cathode region by precisely balancing the pumping speed and gas flow rate. A flow of dust particles/fluid is generated by additional gas injection from a single or dual locations or by altering the dust confining potential. The flow velocity is then estimated by three different techniques, namely, by super particle identification code, particle image velocimetry analysis and the excitation of dust acoustic waves. The results obtained from these three different techniques along with their merits and demerits are discussed. An estimation of the neutral drag force responsible for the generation as well as the attenuation of the dust fluid flow is made. These techniques can be usefully employed in laboratory devices to investigate linear and non-linear collective excitations in a flowing dusty plasma.

  19. High-order harmonic generation in laser plasma plumes

    CERN Document Server

    Ganeev, Rashid A

    2013-01-01

    This book represents the first comprehensive treatment of high-order harmonic generation in laser-produced plumes, covering the principles, past and present experimental status and important applications. It shows how this method of frequency conversion of laser radiation towards the extreme ultraviolet range matured over the course of multiple studies and demonstrated new approaches in the generation of strong coherent short-wavelength radiation for various applications. Significant discoveries and pioneering contributions of researchers in this field carried out in various laser scientific centers worldwide are included in this first attempt to describe the important findings in this area of nonlinear spectroscopy. "High-Order Harmonic Generation in Laser Plasma Plumes" is a self-contained and unified review of the most recent achievements in the field, such as the application of clusters (fullerenes, nanoparticles, nanotubes) for efficient harmonic generation of ultrashort laser pulses in cluster-containin...

  20. Acoustic project for installation of motor generator group by means of computer simulation

    Science.gov (United States)

    Ferreira, Jose C.; Zannin, Paulo T.

    2001-05-01

    This work presents an acoustical project for the installation of a motor generator group of electricity in a hotel by means of computer modeling. The noise levels at the site have been obtained without the motor generator group, and via the computer modeling it has been deduced how these levels would be after the installation of the equipment. A possible solution to mitigate the noise impact the equipment would cause on the neighborhood has been indicated, and it has been predicted how the impact would be reduced after the implantation of this solution.

  1. Laser plasma simulations of the generation processes of Alfven and collisionless shock waves in space plasma

    Science.gov (United States)

    Prokopov, P. A.; Zakharov, Yu P.; Tishchenko, V. N.; Shaikhislamov, I. F.; Boyarintsev, E. L.; Melekhov, A. V.; Ponomarenko, A. G.; Posukh, V. G.; Terekhin, V. A.

    2016-11-01

    Generation of Alfven waves propagating along external magnetic field B0 and Collisionless Shock Waves propagating across B0 are studied in experiments with laser- produced plasma and magnetized background plasma. The collisionless interaction of interpenetrating plasma flows takes place through a so-called Magnetic Laminar Mechanism (MLM) or Larmor Coupling. At the edge of diamagnetic cavity LP-ions produce induction electric field Eφ which accelerates BP-ions while LP-ions rotate in opposite direction. The ions movement generates sheared azimuthal magnetic field Bφ which could launches torsional Alfven wave. In previous experiments at KI-1 large scale facility a generation of strong perturbations propagating across B0 with magnetosonic speed has been studied at a moderate value of interaction parameter δ∼0.3. In the present work we report on experiments at conditions of 5∼R2 and large Alfven-Mach number MA∼10 in which strong transverse perturbations traveling at a scale of ∼1 m in background plasma at a density of ∼3*1013 cm-3 is observed. At the same conditions but smaller MA ∼ 2 a generation, the structure and dynamic of Alfven wave with wavelength ∼0.5 m propagating along fields B0∼100÷500 G for a distance of ∼2.5 m is studied.

  2. Injectable Spontaneous Generation of Tremendous Self-Fueled Liquid Metal Droplet Motors in a Moment

    CERN Document Server

    Yao, You-You; Liu, Jing

    2015-01-01

    Micro motors that could run in liquid environment is very important for a variety of practices such as serving as pipeline robot, soft machine, drug delivery, or microfluidics system etc. However, fabrication of such tiny motors is generally rather time and cost consumptive and has been a tough issue due to involve too many complicated procedures and tools. Here, we show a straightforward injectable way for spontaneously generating autonomously running soft motors in large quantity. A basic fabrication strategy thus enabled is established and illustrated. It was found that, injecting the GaIn alloy pre-fueled with aluminum into electrolyte would automatically split in seconds into tremendous droplet motors swiftly running here and there. The driving force originated from the galvanic cell reaction among alloy, aluminum and surrounding electrolyte which offers interior electricity and hydrogen gas as motion power. This finding opens the possibility to develop injectable tiny-robots, droplet machines or microfl...

  3. Note: High precision angle generator using multiple ultrasonic motors and a self-calibratable encoder

    Science.gov (United States)

    Kim, Jong-Ahn; Kim, Jae Wan; Kang, Chu-Shik; Jin, Jonghan; Bong Eom, Tae

    2011-11-01

    We present an angle generator with high resolution and accuracy, which uses multiple ultrasonic motors and a self-calibratable encoder. A cylindrical air bearing guides a rotational motion, and the ultrasonic motors achieve high resolution over the full circle range with a simple configuration. The self-calibratable encoder can compensate the scale error of a divided circle (signal period: 20″) effectively by applying the equal-division-averaged method. The angle generator configures a position feedback control loop using the readout of the encoder. By combining the ac and dc operation mode, the angle generator produced stepwise angular motion with 0.005″ resolution. We also evaluated the performance of the angle generator using a precision angle encoder and an autocollimator. The expanded uncertainty (k = 2) in the angle generation was estimated less than 0.03″, which included the calibrated scale error and the nonlinearity error.

  4. Generation of novel motor sequences: the neural correlates of musical improvisation.

    Science.gov (United States)

    Berkowitz, Aaron L; Ansari, Daniel

    2008-06-01

    While some motor behavior is instinctive and stereotyped or learned and re-executed, much action is a spontaneous response to a novel set of environmental conditions. The neural correlates of both pre-learned and cued motor sequences have been previously studied, but novel motor behavior has thus far not been examined through brain imaging. In this paper, we report a study of musical improvisation in trained pianists with functional magnetic resonance imaging (fMRI), using improvisation as a case study of novel action generation. We demonstrate that both rhythmic (temporal) and melodic (ordinal) motor sequence creation modulate activity in a network of brain regions comprised of the dorsal premotor cortex, the rostral cingulate zone of the anterior cingulate cortex, and the inferior frontal gyrus. These findings are consistent with a role for the dorsal premotor cortex in movement coordination, the rostral cingulate zone in voluntary selection, and the inferior frontal gyrus in sequence generation. Thus, the invention of novel motor sequences in musical improvisation recruits a network of brain regions coordinated to generate possible sequences, select among them, and execute the decided-upon sequence.

  5. On parallel electric field generation in transversely inhomogeneous plasmas

    CERN Document Server

    Tsiklauri, David

    2007-01-01

    The generation of parallel electric fields by the propagation of ion cyclotron waves in the plasma with a transverse density inhomogeneity was studied. It was proven that the minimal model required to reproduce the previous kinetic simulation results of E_{||} generation [Tsiklauri et al 2005, Genot et al 2004] is the two-fluid, cold plasma approximation in the linear regime. By considering the numerical solutions it was also shown that the cause of E_{||} generation is the electron and ion flow separation induced by the transverse density inhomogeneity. We also investigate how E_{||} generation is affected by the mass ratio and found that amplitude attained by E_{||} decreases linearly as inverse of the mass ratio m_i/m_e. For realistic mass ratio of m_i/m_e=1836, such empirical scaling law, within a time corresponding to 3 periods of the driving ion cyclotron wave, is producing E_{||}=14 Vm^{-1} for solar coronal parameters. Increase in mass ratio does not have any effect on final parallel (magnetic field a...

  6. Electron beam generated plasmas for the processing of graphene

    Science.gov (United States)

    Walton, S. G.; Hernández, S. C.; Boris, D. R.; Petrova, Tz B.; Petrov, G. M.

    2017-09-01

    The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma and applied it to the processing of graphene. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc), the plasma is driven by a high-energy (~few keV) electron beam, an approach that simplifies the relative production of species while providing comparatively high ion-to-radical production rates. The resulting plasmas are characterized by high charged particle densities (1010-1011 cm-3) and electron temperatures that are typically about 1.0 eV or lower. Accordingly, the flux to adjacent surfaces is generally dominated by ions with kinetic energies in the range of 1-5 eV, a value at or near the bond strength of most materials. This provides the potential for controllably engineering materials with monolayer precision, an attribute attractive for the processing of atomically thin material systems. This work describes the attributes of electron beam driven plasma processing system and its use in modification of graphene.

  7. Laser propagation and soliton generation in strongly magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Feng, W.; Li, J. Q.; Kishimoto, Y. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2016-03-15

    The propagation characteristics of various laser modes with different polarization, as well as the soliton generation in strongly magnetized plasmas are studied numerically through one-dimensional (1D) particle-in-cell (PIC) simulations and analytically by solving the laser wave equation. PIC simulations show that the laser heating efficiency substantially depends on the magnetic field strength, the propagation modes of the laser pulse and their intensities. Generally, large amplitude laser can efficiently heat the plasma with strong magnetic field. Theoretical analyses on the linear propagation of the laser pulse in both under-dense and over-dense magnetized plasmas are well confirmed by the numerical observations. Most interestingly, it is found that a standing or moving soliton with frequency lower than the laser frequency is generated in certain magnetic field strength and laser intensity range, which can greatly enhance the laser heating efficiency. The range of magnetic field strength for the right-hand circularly polarized (RCP) soliton formation with high and low frequencies is identified by solving the soliton equations including the contribution of ion's motion and the finite temperature effects under the quasi-neutral approximation. In the limit of immobile ions, the RCP soliton tends to be peaked and stronger as the magnetic field increases, while the enhanced soliton becomes broader as the temperature increases. These findings in 1D model are well validated by 2D simulations.

  8. Material for electrodes of low temperature plasma generators

    Science.gov (United States)

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

    2008-12-09

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  9. The interaction of explosively generated plasma with explosives

    Science.gov (United States)

    Tasker, Douglas G.; Whitley, Von H.; Johnson, Carl E.

    2017-01-01

    It has been shown that the temperature of explosively generated plasma (EGP) is of the order of 1 eV and plasma ejecta can be focused to achieve velocities as high as 25 km/s. Proof-of-principle tests were performed to determine if EGP could be used for explosive ordnance demolition and other applications. The goals were: to benignly disable ordnance containing relatively sensitive high performance explosives (PBX-9501); and to investigate the possibility of interrupting an ongoing detonation in a powerful high explosive (again PBX-9501) with EGP. Experiments were performed to establish the optimum sizes of plasma generators for the benign deactivation of high explosives, i.e., the destruction of the ordnance without initiating a detonation or comparable violent event. These experiments were followed by attempts to interrupt an ongoing detonation by the benign disruption of the unreacted explosive in its path. The results were encouraging. First, it was demonstrated that high explosives could be destroyed without the initiation of a detonation or high order reaction. Second, ongoing detonations were successfully interrupted with EGP. [LA-UR-15-25350

  10. Nonthermal Argon Plasma Generator and Some Potential Applications

    Directory of Open Access Journals (Sweden)

    Bunoiu M.

    2015-12-01

    Full Text Available A laboratory - made nonthermal plasma generator is presented. It has a diameter of 0.020 m and length of 0.155 m and contains two electrodes. The first electrode is a 2% Th-W alloy, 0.002 m in diameter bar, centred inside the generator’s body by means of a four channel teflon piece; the other three channels, 0.003 m in diameter, are used for Ar supply. The second electrode is a nozzle of 0.002 m - 0.008 m diameter and 0.005m length. A ~500 kV/m electric field is generated between the two electrodes by a high frequency source (13.56 MHz ±5%, equipped with a OT-1000 (Tungsram power triode. For Ar flows ranging from 0.00008 m3/s to 0.00056 m3/s, a plasma jet of length not exceeding 0.015 m and temperature below 315 K is obtained. Anthurium andraeanumis sample , blood matrix, human hair and textile fibers may be introduced in the plasma jet. For time periods of 30 s and 60 s, various effects like, cell detexturization, fast blood coagulation or textile fiber or hair cleaning and smoothing are obtained. These effects are presented and discussed in the paper.

  11. Design of a motor-generator for an energy storage flywheel

    Science.gov (United States)

    Niemeyer, W. Leland; Studer, Philip A.

    1988-01-01

    The paper examines motor/generator designs in which the rotor is integrated into the flywheel. Rotational loss considerations tend to dominate the design tradeoffs to maintain high system storage efficiency with a directly coupled unit. Some of the design alternatives are described as a guide to the experimental and analytical program needed to finalize a design.

  12. Solar Wind Strahl Broadening by Self-Generated Plasma Waves

    Science.gov (United States)

    Pavan, J.; Vinas, A. F.; Yoon, P. H.; Ziebell, L. F.; Gaelzer, R.

    2013-01-01

    This Letter reports on the results of numerical simulations which may provide a possible explanation for the strahl broadening during quiet solar conditions. The relevant processes involved in the broadening are due to kinetic quasi-linear wave-particle interaction. Making use of static analytical electron distribution in an inhomogeneous field, it is found that self-generated electrostatic waves at the plasma frequency, i.e., Langmuir waves, are capable of scattering the strahl component, resulting in energy and pitch-angle diffusion that broadens its velocity distribution significantly. The present theoretical results provide an alternative or complementary explanation to the usual whistler diffusion scenario, suggesting that self-induced electrostatic waves at the plasma frequency might play a key role in broadening the solar wind strahl during quiet solar conditions.

  13. Slow electrostatic fluctuations generated by beam-plasma interaction

    CERN Document Server

    Pommois, Karen; Pezzi, Oreste; Veltri, Pierluigi

    2016-01-01

    Eulerian simulations of the Vlasov-Poisson equations have been employed to analyze the excitation of slow electrostatic fluctuations (with phase speed close to the electron thermal speed), due to a beam-plasma interaction, and their propagation in linear and nonlinear regime. In 1968, O'Neil and Malmberg [Phys. Fluids {\\bf 11}, 1754 (1968)] dubbed these waves "beam modes". In the present paper, it is shown that, in the presence of a cold and low density electron beam, these beam modes can become unstable and then survive Landau damping unlike the Langmuir waves. When an electron beam is launched in a plasma of Maxwellian electrons and motionless protons and this initial equilibrium is perturbed by a monochromatic density disturbance, the electric field amplitude grows exponentially in time and then undergoes nonlinear saturation, associated with the kinetic effects of particle trapping and phase space vortex generation. Moreover, if the initial density perturbation is setup in the form of a low amplitude rand...

  14. Shock Generation and Control Using DBD Plasma Actuators

    Science.gov (United States)

    Patel, Mehul P.; Cain, Alan B.; Nelson, Christopher C.; Corke, Thomas C.; Matlis, Eric H.

    2012-01-01

    This report is the final report of a NASA Phase I SBIR contract, with some revisions to remove company proprietary data. The Shock Boundary Layer Interaction (SBLI) phenomena in a supersonic inlet involve mutual interaction of oblique shocks with boundary layers, forcing the boundary layer to separate from the inlet wall. To improve the inlet efficiency, it is desired to prevent or delay shock-induced boundary layer separation. In this effort, Innovative Technology Applications Company (ITAC), LLC and the University of Notre Dame (UND) jointly investigated the use of dielectric-barrier-discharge (DBD) plasma actuators for control of SBLI in a supersonic inlet. The research investigated the potential for DBD plasma actuators to suppress flow separation caused by a shock in a turbulent boundary layer. The research involved both numerical and experimental investigations of plasma flow control for a few different SBLI configurations: (a) a 12 wedge flow test case at Mach 1.5 (numerical and experimental), (b) an impinging shock test case at Mach 1.5 using an airfoil as a shock generator (numerical and experimental), and (c) a Mach 2.0 nozzle flow case in a simulated 15 X 15 cm wind tunnel with a shock generator (numerical). Numerical studies were performed for all three test cases to examine the feasibility of plasma flow control concepts. These results were used to guide the wind tunnel experiments conducted on the Mach 1.5 12 degree wedge flow (case a) and the Mach 1.5 impinging shock test case (case b) which were at similar flow conditions as the corresponding numerical studies to obtain experimental evidence of plasma control effects for SBLI control. The experiments also generated data that were used in validating the numerical studies for the baseline cases (without plasma actuators). The experiments were conducted in a Mach 1.5 test section in the University of Notre Dame Hessert Laboratory. The simulation results from cases a and b indicated that multiple

  15. Concepts for using trapped-flux HTS in motors and generators

    Science.gov (United States)

    Hull, John R.; Strasik, Michael

    2013-01-01

    We examine the expected performance of a brushless motor/generator that uses trapped-flux (TF) bulk high-temperature superconductors (HTSs) to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium (Dy) for the stator and rotor cores. We also examine methods to energize TF in HTS for generators used in pulsed-power applications.

  16. An enantioselective synthetic route toward second-generation light-driven rotary molecular motors.

    Science.gov (United States)

    Pijper, Thomas C; Pijper, Dirk; Pollard, Michael M; Dumur, Frédéric; Davey, Stephen G; Meetsma, Auke; Feringa, Ben L

    2010-02-05

    Controlling the unidirectional rotary process of second-generation molecular motors demands access to these motors in their enantiomerically pure form. In this paper, we describe an enantioselective route to three new second-generation light-driven molecular motors. Their synthesis starts with the preparation of an optically active alpha-methoxy-substituted upper-half ketone involving an enzymatic resolution. The subsequent conversion of this ketone to the corresponding hydrazone by treatment with hydrazine led to full racemization. However, conversion to a TBDMS-protected hydrazone by treatment with bis-TBDMS hydrazine, prepared according to a new procedure, proceeds with nearly full retention of the stereochemical integrity. Oxidation of the TBDMS-protected hydrazone and subsequent coupling to a lower-half thioketone followed by recrystallization provided the molecular motors with >99% ee. As these are the first molecular motors that have a methoxy substituent at the stereogenic center, the photochemical and thermal isomerization steps involved in the rotary cycle of one of these new molecules were studied in detail with various spectroscopic techniques.

  17. Magnetic field generation during intense laser channelling in underdense plasma

    Science.gov (United States)

    Smyth, A. G.; Sarri, G.; Vranic, M.; Amano, Y.; Doria, D.; Guillaume, E.; Habara, H.; Heathcote, R.; Hicks, G.; Najmudin, Z.; Nakamura, H.; Norreys, P. A.; Kar, S.; Silva, L. O.; Tanaka, K. A.; Vieira, J.; Borghesi, M.

    2016-06-01

    Channel formation during the propagation of a high-energy (120 J) and long duration (30 ps) laser pulse through an underdense deuterium plasma has been spatially and temporally resolved via means of a proton imaging technique, with intrinsic resolutions of a few μm and a few ps, respectively. Conclusive proof is provided that strong azimuthally symmetric magnetic fields with a strength of around 0.5 MG are created inside the channel, consistent with the generation of a collimated beam of relativistic electrons. The inferred electron beam characteristics may have implications for the cone-free fast-ignition scheme of inertial confinement fusion.

  18. GDNF plasma levels in spina bifida: correlation with severity of spinal damage and motor function.

    Science.gov (United States)

    Chiaretti, Antonio; Rendeli, Claudia; Antonelli, Alessia; Barone, Giuseppe; Focarelli, Benedetta; Tabacco, Fabrizia; Massimi, Luca; Ausili, Emanuele

    2008-12-01

    Glial-derived neurotrophic factor (GDNF) is one of several powerful survival factors for spinal motoneurons that play a key role in sprouting, synaptic plasticity, and reorganization after spinal cord damage. The aim of this study was to investigate the expression of GDNF in plasma of children with spina bifida (SB) and to determine its correlation with both the severity of spinal cord damage and the motor function of these patients. To measure the GDNF expression, we collected plasma samples from 152 children with SB and in 149 matched controls. Endogenous GDNF levels were quantified using a two-site immuno-enzymatic assay. The statistical analysis was performed using the Mann-Whitney two-tailed two-sample test. In children with SB the mean levels of GDNF (131.2 +/- 69.6 pg/mL) were significantly higher (p spine injury.

  19. Flywheel induction motor-generator for magnet power supply in small fusion device

    Science.gov (United States)

    Hatakeyma, S.; Yoshino, F.; Tsutsui, H.; Tsuji-Iio, S.

    2016-04-01

    A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).

  20. Generation of attosecond electron bunches in a laser-plasma accelerator using a plasma density upramp

    Energy Technology Data Exchange (ETDEWEB)

    Weikum, M.K., E-mail: maria.weikum@desy.de [Deutsches Elektronensynchrotron (DESY), Bdg. 30b, Notkestr. 85, 22607 Hamburg (Germany); Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Li, F.Y. [Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Assmann, R.W. [Deutsches Elektronensynchrotron (DESY), Bdg. 30b, Notkestr. 85, 22607 Hamburg (Germany); Sheng, Z.M. [Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Laboratory for Laser Plasmas and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Jaroszynski, D. [Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom)

    2016-09-01

    Attosecond electron bunches and attosecond radiation pulses enable the study of ultrafast dynamics of matter in an unprecedented regime. In this paper, the suitability for the experimental realization of a novel scheme producing sub-femtosecond duration electron bunches from laser-wakefield acceleration in plasma with self-injection in a plasma upramp profile has been investigated. While it has previously been predicted that this requires laser power above a few hundred terawatts typically, here we show that the scheme can be extended with reduced driving laser powers down to tens of terawatts, generating accelerated electron pulses with minimum length of around 166 attoseconds and picocoulombs charge. Using particle-in-cell simulations and theoretical models, the evolution of the accelerated electron bunch within the plasma as well as simple scalings of the bunch properties with initial laser and plasma parameters are presented. - Highlights: • LWFA with an upramp density profile can trap and accelerate sub-fs electron beams. • A reduction of the necessary threshold laser intensity by a factor 4 is presented. • Electron properties are tuned by varying initial laser and plasma parameters. • Simulations predict electron bunch lengths below 200 attoseconds with pC charge. • Strong bunch evolution effects and a large energy spread still need to be improved.

  1. Vectorial Command of Induction Motor Pumping System Supplied by a Photovoltaic Generator

    Science.gov (United States)

    Makhlouf, Messaoud; Messai, Feyrouz; Benalla, Hocine

    2011-01-01

    With the continuous decrease of the cost of solar cells, there is an increasing interest and needs in photovoltaic (PV) system applications following standard of living improvements. Water pumping system powered by solar-cell generators are one of the most important applications. The fluctuation of solar energy on one hand, and the necessity to optimise available solar energy on the other, it is useful to develop new efficient and flexible modes to control motors that entrain the pump. A vectorial control of an asynchronous motor fed by a photovoltaic system is proposed. This paper investigates a photovoltaic-electro mechanic chain, composed of a PV generator, DC-AC converter, a vector controlled induction motor and centrifugal pump. The PV generator is forced to operate at its maximum power point by using an appropriate search algorithm integrated in the vector control. The optimization is realized without need to adding a DC-DC converter to the chain. The motor supply is also ensured in all insolation conditions. Simulation results show the effectiveness and feasibility of such an approach.

  2. Brushless DC motor control system responsive to control signals generated by a computer or the like

    Science.gov (United States)

    Packard, Douglas T. (Inventor); Schmitt, Donald E. (Inventor)

    1987-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The rotor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor may be regulated by applying a separate control signal to each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  3. Calibrated automated thrombin generation measurement in clotting plasma.

    Science.gov (United States)

    Hemker, H Coenraad; Giesen, Peter; Al Dieri, Raed; Regnault, Véronique; de Smedt, Eric; Wagenvoord, Rob; Lecompte, Thomas; Béguin, Suzette

    2003-01-01

    Calibrated automated thrombography displays the concentration of thrombin in clotting plasma with or without platelets (platelet-rich plasma/platelet-poor plasma, PRP/PPP) in up to 48 samples by monitoring the splitting of a fluorogenic substrate and comparing it to a constant known thrombin activity in a parallel, non-clotting sample. Thus, the non-linearity of the reaction rate with thrombin concentration is compensated for, and adding an excess of substrate can be avoided. Standard conditions were established at which acceptable experimental variation accompanies sensitivity to pathological changes. The coefficients of variation of the surface under the curve (endogenous thrombin potential) are: within experiment approximately 3%; intra-individual: AVK, heparin(-likes), direct inhibitors]. In PRP, it is diminished in von Willebrand's disease, but it also shows the effect of platelet inhibitors (e.g. aspirin and abciximab). Addition of activated protein C (APC) or thrombomodulin inhibits thrombin generation and reflects disorders of the APC system (congenital and acquired resistance, deficiencies and lupus antibodies) independent of concomitant inhibition of the procoagulant pathway as for example by anticoagulants.

  4. Ge laser-generated plasma for ion implantation

    Science.gov (United States)

    Giuffrida, L.; Torrisi, L.; Czarnecka, A.; Wołowski, J.; Quarta, Ge; Calcagnile, L.; Lorusso, A.; Nassisi, V.

    Laser-generated plasma obtained by Ge ablation in vacuum was investigated with the aim to implant energetic Ge ions in light substrates (C, Si, SiO2). Different intensities of laser sources were employed for these experiments: Nd:Yag of Catania-LNS; Nd:Yag of Warsaw-IPPL; excimer laser of Lecce-INFN; iodine laser of Prague-PALS. Different experimental setups were used to generate multiple ion stream emissions, multiple ion energetic distributions, high implantation doses, thin film deposition and post-acceleration effects. `On line' measurements of ion energy were obtained with ion collectors and ion energy analyzer in time-of-flight configuration. `Off line' measurement of Ge implants were obtained with 2.25 MeV helium beam in Rutherford backscattering spectrometry. Results indicated that ion implants show typical deep profiles only for substrates placed along the normal to the target surface at which the ion energy is maximum.

  5. Peculiarities of Efficient Plasma Generation in Air and Water by Short Duration Laser Pulses

    Science.gov (United States)

    Adamovsky, Grigory; Floyd, Bertram M.

    2017-01-01

    We have conducted experiments to demonstrate an efficient generation of plasma discharges by focused nanosecond pulsed laser beams in air and provided recommendations on the design of optical systems to implement such plasma generation. We have also demonstrated generation of the secondary plasma discharge using the unused energy from the primary one. Focused nanosecond pulsed laser beams have also been utilized to generate plasma in water where we observed self-focusing and filamentation. Furthermore, we applied the laser generated plasma to the decomposition of methylene blue dye diluted in water.

  6. Bernstein wave aided laser third harmonic generation in a plasma

    Science.gov (United States)

    Tyagi, Yachna; Tripathi, Deepak; Kumar, Ashok

    2016-09-01

    The process of Bernstein wave aided resonant third harmonic generation of laser in a magnetized plasma is investigated. The extra-ordinary mode (X-mode) laser of frequency ω 0 and wave number k → 0 , travelling across the magnetic field in a plasma, exerts a second harmonic ponderomotive force on the electrons imparting them an oscillatory velocity v → 2 ω0 , 2 k → 0 . This velocity beats with the density perturbation due to the Bernstein wave to produce a density perturbation at cyclotron frequency shifted second harmonic. The density perturbation couples with the oscillatory velocity v → ω0 , k → 0 of X-mode of the laser to produce the cyclotron frequency shifted third harmonic current density leading to harmonic radiation. The phase matching condition for the up shifted frequency is satisfied when the Bernstein wave is nearly counter-propagating to the laser. As the transverse wave number of the Bernstein wave is large, it is effective in the phase matched third harmonic generation, when the laser frequency is not too far from the upper hybrid frequency.

  7. Flowing dusty plasma experiments: Generation of flow and measurement techniques

    CERN Document Server

    Jaiswal, S; Sen, A

    2016-01-01

    A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a $\\Pi-$shaped Dusty Plasma Experimental (DPEx) device with micron size kaolin/Melamine Formaldehyde (MF) particles embedded in a background of Argon plasma created by a direct current (DC) glow discharge. A stationary dust cloud is formed over the cathode region by precisely balancing the pumping speed and gas flow rate. A flow of dust particles/fluid is generated by additional gas injection from a single or dual locations or by altering the dust confining potential. The flow velocity is then estimated by three different techniques, namely, by super Particle Identification (sPIT) code, Particle Image Velocimetry (PIV) analysis and the excitation of Dust Acoustic Waves (DAWs). The results obtained from these three different techniques along with their merits and demerits are discussed. An estimation of the neutral dr...

  8. Nuclear Fusion Effects Induced in Intense Laser-Generated Plasmas

    Directory of Open Access Journals (Sweden)

    Lorenzo Torrisi

    2013-01-01

    Full Text Available Deutered polyethylene (CD2n thin and thick targets were irradiated in high vacuum by infrared laser pulses at 1015W/cm2 intensity. The high laser energy transferred to the polymer generates plasma, expanding in vacuum at supersonic velocity, accelerating hydrogen and carbon ions. Deuterium ions at kinetic energies above 4 MeV have been measured by using ion collectors and SiC detectors in time-of-flight configuration. At these energies the deuterium–deuterium collisions may induce over threshold fusion effects, in agreement with the high D-D cross-section valuesaround 3 MeV energy. At the first instants of the plasma generation, during which high temperature, density and ionacceleration occur, the D-D fusions occur as confirmed by the detection of mono-energetic protonsand neutrons with a kinetic energy of 3.0 MeV and 2.5 MeV, respectively, produced by the nuclear reaction. The number of fusion events depends strongly on the experimental set-up, i.e. on the laser parameters (intensity, wavelength, focal spot dimension, target conditions (thickness, chemical composition, absorption coefficient, presence of secondary targets and used geometry (incidence angle, laser spot, secondary target positions.A number of D-D fusion events of the order of 106÷7 per laser shot has been measured.

  9. High duty factor plasma generator for CERN's Superconducting Proton Linac.

    Science.gov (United States)

    Lettry, J; Kronberger, M; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, J-M; Küchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-02-01

    CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H(-) volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H(-) during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H(-) during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H(-) plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H(-) source operating at SNS.

  10. Development of Voltage Sag Compensator and UPS using a Flywheel Induction Motor and an Engine Generator

    Science.gov (United States)

    Kato, Shuhei; Takaku, Taku; Sumitani, Hideo; Shimada, Ryuichi

    Flywheel energy storage systems are focused as uninterruptible power supplies (UPS) from the viewpoint of environmental friendliness and high durability performance. Using a low-speed and heavy flywheel, and a low-cost squirrel-cage induction motor/generator, two applications are proposed; 1) 11kW voltage sag compensator using a capacitor self-excited induction generator without semiconductor converters; 2) UPS composed of the flywheel system and an engine generator. From some experimental results, an ideal voltage sag compensator and UPS are realized by the low-technology flywheel system.

  11. Promoting Plasma Physics as a Career: A Generational Approach

    Science.gov (United States)

    Morgan, James

    2005-10-01

    A paradigm shift is occurring in education physics programs. Educators are shifting from the traditional teaching focus to concentrate on student learning. Students are unaware of physics as a career, plasma physics or the job opportunities afforded to them with a physics degree. The physics profession needs to promote itself to the younger generations, or specifically the millennial generation (Born in the 1980's-2000's). Learning styles preferred by ``Millennials'' include a technological environment that promotes learning through active task performance rather than passive attendance at lectures. Millennials respond well to anything experiential and will be motivated by opportunities for creativity and challenging learning environments. The open-ended access to information, the ability to tailor learning paths, and continuous and instantaneous performance assessment offer flexibility in the design of curricula as well as in the method of delivery. Educators need to understand the millennial generation, appeal to their motivations and offer a learning environment designed for their learning style. This poster suggests promoting a physics career by focusing on generational learning styles and preferences.

  12. Baseline Plasma C-Reactive Protein Concentrations and Motor Prognosis in Parkinson Disease.

    Directory of Open Access Journals (Sweden)

    Atsushi Umemura

    Full Text Available C-reactive protein (CRP, a blood inflammatory biomarker, is associated with the development of Alzheimer disease. In animal models of Parkinson disease (PD, systemic inflammatory stimuli can promote neuroinflammation and accelerate dopaminergic neurodegeneration. However, the association between long-term systemic inflammations and neurodegeneration has not been assessed in PD patients.To investigate the longitudinal effects of baseline CRP concentrations on motor prognosis in PD.Retrospective analysis of 375 patients (mean age, 69.3 years; mean PD duration, 6.6 years. Plasma concentrations of high-sensitivity CRP were measured in the absence of infections, and the Unified Parkinson's Disease Rating Scale Part III (UPDRS-III scores were measured at five follow-up intervals (Days 1-90, 91-270, 271-450, 451-630, and 631-900.Change of UPDRS-III scores from baseline to each of the five follow-up periods.Change in UPDRS-III scores was significantly greater in PD patients with CRP concentrations ≥0.7 mg/L than in those with CRP concentrations <0.7 mg/L, as determined by a generalized estimation equation model (P = 0.021 for the entire follow-up period and by a generalized regression model (P = 0.030 for the last follow-up interval (Days 631-900. The regression coefficients of baseline CRP for the two periods were 1.41 (95% confidence interval [CI] 0.21-2.61 and 2.62 (95% CI 0.25-4.98, respectively, after adjusting for sex, age, baseline UPDRS-III score, dementia, and incremental L-dopa equivalent dose.Baseline plasma CRP levels were associated with motor deterioration and predicted motor prognosis in patients with PD. These associations were independent of sex, age, PD severity, dementia, and anti-Parkinsonian agents, suggesting that subclinical systemic inflammations could accelerate neurodegeneration in PD.

  13. Analysis of mechanical behavior and hysteresis heat generating mechanism of PDM motor

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Changshuai; Zhu, Xiaohua; Tang, Liping [Southwest Petroleum University, Chengdu (China); Deng, Juan [Avic Chengdu Engine (Group) Co.,Ltd, Chengdu (China)

    2017-03-15

    Positive displacement motor (PDM), which is prone to high temperature fatigue failure, can be weakened in its application in deep and superdeep well. In order to study the forced state, deformation regularity and thermal hysteresis of PDM motor, the paper established the three-dimensional thermal-mechanical coupled Finite element model (FEM). Based on the theoretical research, experimental study and numerical simulation, the study found that the displacement of stator lining shows a sinusoidal variation under internal pressure, when adapting the general form of sine function to fitting inner contour line deformation function. Then the paper analyzed the hysteresis heat generating mechanism of the motor, learning that hysteresis thermogenous of stator lining occurs due to the viscoelastic of rubber material and cyclic loading of stator lining. A heartburn happens gradually in the center of the thickest part of the stator lining as temperature increases, which means work efficiency and service life of PDM will be decreased when used in deep or superdeep well. In this paper, we established a theory equation for the choice of interference fit and motor line type optimization design, showing hysteresis heat generating analyzing model and method are reasonable enough to significantly improve PDM’s structure and help better use PDM in deep and surdeep well.

  14. The flagellar motor of Caulobacter crescentus generates more torque when a cell swims backwards

    Science.gov (United States)

    Lele, Pushkar P.; Roland, Thibault; Shrivastava, Abhishek; Chen, Yihao; Berg, Howard C.

    2016-02-01

    The bacterium Caulobacter crescentus swims by rotating a single right-handed helical filament. These cells have two swimming modes: a pusher mode, in which clockwise (CW) rotation of the filament thrusts the cell body forwards, and a puller mode, in which counterclockwise (CCW) rotation pulls it backwards. The situation is reversed in Escherichia coli, a bacterium that rotates several left-handed filaments CCW to drive the cell body forwards. The flagellar motor in E. coli generates more torque in the CCW direction than the CW direction in swimming cells. However, C. crescentus and other bacteria with single filaments swim forwards and backwards at similar speeds, prompting the assumption that motor torques in the two modes are the same. Here, we present evidence that motors in C. crescentus develop higher torques in the puller mode than in the pusher mode, and suggest that the anisotropy in torque generation is similar in the two species, despite the differences in filament handedness and motor bias.

  15. Research on Switched Reluctance Motor for Automobile Starter/Generator System

    Institute of Scientific and Technical Information of China (English)

    QUAN Li; LIU Qiang; ZHAO De-an; LIU Di-ji

    2006-01-01

    A self-designed and developed 12/10 switched reluctance motor(SRM)is chosen as the object of study and a prototype of 2.5 kW switched reluctance starter/generator with fly-wheel is designed based on the requirements of the selected engine (Changan Aotooc three-cylinder engine wagon) for the starter, generator and drive. The 36 V/42 V DC source system is applied to establishing the simulation-analyzing model of the motor. A finite-element (FE) analysis of its two-dimensional electromagnetic field is conducted to obtain the exact model of the motor. Systematic simulation is carried out combining with its power conversion circuit and control element. Meanwhile the starting process and performance of the system are studied and analyzed with special efforts. Satisfactory result is derived from the testing of the prototype:theoretical analysis is basically matched with the tested data, which proves the rationality and feasibility of the design procedures, systematic modeling and control strategies. Therefore, the new 12/10-structure scheme is put forward based on the development and analysis of various SRM and it meets the requirements of the researched motor in terms of the structural parameters.

  16. Operational characteristics of the high flux plasma generator Magnum-PSI

    NARCIS (Netherlands)

    van Eck, H. J. N.; Abrams, T.; van den Berg, M. A.; Brons, S.; van Eden, G. G.; Jaworski, M. A.; Kaita, R.; van der Meiden, H. J.; Morgan, T. W.; van de Pol, M.J.; Scholten, J.; Smeets, P. H. M.; De Temmerman, G.; de Vries, P. C.; van Emmichoven, P. A. Zeijlma

    2014-01-01

    Abstract In Magnum-PSI (MAgnetized plasma Generator and \\{NUMerical\\} modeling for Plasma Surface Interactions), the high density, low temperature plasma of a wall stabilized dc cascaded arc is confined to a magnetized plasma beam by a quasi-steady state axial magnetic field up to 1.3 T. It

  17. An extended motor network generates beta and gamma oscillatory perturbations during development

    OpenAIRE

    Wilson, Tony W.; Slason, Erin; Asherin, Ryan; Kronberg, Eugene; Reite, Martin L.; Teale, Peter D.; Donald C Rojas

    2010-01-01

    This study examines the time course and neural generators of oscillatory beta and gamma motor responses in typically-developing children. Participants completed a unilateral flexion-extension task using each index finger as whole-head magnetoencephalography (MEG) data were acquired. These MEG data were imaged in the frequency-domain using spatial filtering and the resulting event-related synchronizations and desynchronizations (ERS/ERD) were subjected to voxel-wise statistical analyses to ill...

  18. Aerosol generation by blower motors as a bias in assessing aerosol penetration into cabin filtration systems.

    Science.gov (United States)

    Heitbrink, William A; Collingwood, Scott

    2005-01-01

    In cabin filtration systems, blower motors pressurize a vehicle cabin with clean filtered air and recirculate air through an air-conditioning evaporator coil and a heater core. The exposure reduction offered by these cabins is evaluated by optical particle counters that measure size-dependent aerosol concentration inside and outside the cabin. The ratio of the inside-to-outside concentration is termed penetration. Blower motors use stationary carbon brushes to transmit an electrical current through a rotating armature that abrades the carbon brushes. This creates airborne dust that may affect experimental evaluations of aerosol penetration. To evaluate the magnitude of these dust emissions, blower motors were placed in a test chamber and operated at 12 and 13.5 volts DC. A vacuum cleaner drew 76 m3/hour (45 cfm) of air through HEPA filters, the test chamber, and through a 5 cm diameter pipe. An optical particle counter drew air through an isokinetic sampling probe and measured the size-dependent particle concentrations from 0.3 to 15 microm. The concentration of blower motor aerosol was between 2 x 10(5) and 1.8 x 10(6) particles/m3. Aerosol penetration into three stationary vehicles, two pesticide application vehicles and one tractor were measured at two conditions: low concentration (outside in the winter) and high concentration (inside repair shops and burning incense sticks used as a supplemental aerosol source). For particles smaller than 1 microm, the in-cabin concentrations can be explained by the blower motor emissions. For particles larger than 1 microm, other aerosol sources, such as resuspended dirt, are present. Aerosol generated by the operation of the blower motor and by other sources can bias the exposure reduction measured by optical particle counters.

  19. Local Magnetohydrodynamic Characteristics of the Plasma Stream generated by MPC

    Directory of Open Access Journals (Sweden)

    Tatyana N. Cherednychenko

    2013-01-01

    Full Text Available This paper investigates the spatial distributions of electrical current which flows inside the plasma stream generated by a magnetoplasma compressor (MPC. Two different modes of MPC operation with different gas supply scenarios have been applied in the experiments presented here. The first is the operation mode with a pulse injection of xenon into the interelectrode space, and the second is the operation mode with residual helium in the chamber and local injection of xenon directly into the compression zone. The maximum value of the electric current observed outside the MPC channel is 15 ÷ 20% of the total discharge current. Electric current vortices were discovered in the plasma stream. The amplitude of the current in the vortices reaches 50% of the total discharge current. The maximum EUV radiation power was measured in the mode of MPC operation with local xenon injection. Power in the wave range 12.2 ÷ 15.8 nm achieves up to 16 ÷ 18 kW.

  20. Silicon carbide detector for laser-generated plasma radiation

    Science.gov (United States)

    Bertuccio, Giuseppe; Puglisi, Donatella; Torrisi, Lorenzo; Lanzieri, Claudio

    2013-05-01

    We present the performance of a Silicon Carbide (SiC) detector in the acquisition of the radiation emitted by laser generated plasmas. The detector has been employed in time of flight (TOF) configuration within an experiment performed at the Prague Asterix Laser System (PALS). The detector is a 5 mm2 area 100 nm thick circular Nisbnd SiC Schottky junction on a high purity 4Hsbnd SiC epitaxial layer 115 μm thick. Current signals from the detector with amplitudes up to 1.6 A have been measured, achieving voltage signals over 80 V on a 50 Ω load resistance with excellent signal to noise ratios. Resolution of few nanoseconds has been experimentally demonstrated in TOF measurements. The detector has operated at 250 V DC bias under extreme operating conditions with no observable performance degradation.

  1. Complete Study of the Phase Advancing in the Switched Reluctance Motor/Standalone Generator

    Directory of Open Access Journals (Sweden)

    Majid Asgar

    2014-12-01

    Full Text Available The switched reluctance motor is a singly excited, doubly salient machine which can be used in the generation mode by selecting the proper firing angles of the phases. Due to its robustness, it has the potential and the ability to become one of the generators to be used in the harsh environment. This paper briefly discusses the energy conversion by a switched reluctance generator (SRG when two switches per phase converter circuit and discrete position sensors are employed. It is well known fact that, as the generator’s speed increases by a prime mover and the shape of the current waveform changes in such a way that limits the production of generating voltage. At high speeds, it is possible for the phase current never reaches the desired value to produce enough back-EMF for sufficient voltage generation, therefore, the output power falls off. In order to remedy this problem, the phase turn on angle is advanced in a way that the phase commutation begins sooner. Since one of the advantages of this type of generator is its variable speed then, the amount of advancing for the turn on angle should be accomplished automatically to obtain the desired output voltage according to the speed of the generator, meaning, as the generator speed increases so should the turn on angle and vice versa. In this respect, this paper introduces an electronic circuit in conjunction with time reshaping of the command pulses obtained from position sensors and the drive converter to achieve this task for a desired output voltage when a SRG feeding a resistive load. To evaluate the generator performance, two types of analysis, namely numerical technique and experimental studies have been utilized on a 6 by 4, 30 V, SRG. In the numerical analysis, due to the highly non-linear nature of the motor, a three dimensional finite element analysis is employed to calculate some of motor parameters and then using these parameter, current shape and magnitude are computed, whereas in

  2. Coupling of a RF generator to a plasma reactor; Acoplamiento de un generador RF a un reactor de plasma

    Energy Technology Data Exchange (ETDEWEB)

    Salazar T, J.A

    2003-07-01

    The following thesis presents the development of the generation from a capacitive plasma through of radiofrequency discharges, for their realization it was needed of a series of elements capable of development such task, as they are it: the RF generator, the couple circuit of impedances and a plasma reactor. The main characteristics of each part is also described that composes the one system, as well as the results obtained experimentally, calculations and the devices used and designed to generate the capacitive thermal plasma. Moreover, is sought that this joining system is the base for later developments in those that intervene the generation of a capacitive plasma and one can to consider for practical and theoretical developments in the improvement of other processes as they are it: the generation of particles of carbon with different gases and hydrocarbons, the polymerization of metals, to synthesize pure molecules, for illumination purposes, etc. (Author)

  3. Generation of low-temperature plasma by low-pressure arcs for synthesis of nitride coatings

    Science.gov (United States)

    Krysina, O. V.; Koval, N. N.; Lopatin, I. V.; Shugurov, V. V.; Kovalsky, S. S.

    2016-01-01

    Experiments were performed to study gas, metal, and mixed metal-gas plasmas. The plasmas were generated with the use of an arc evaporator and a gas-plasma source with a hot filament and hollow cathode that were operated independently or simultaneously. It has been revealed that the arc current of gas-plasma source affects the parameters of the metal-gas plasma and the element concentrations in the coatings. It has been demonstrated that the characteristics of the nitride coatings produced by plasma-assisted vacuum-arc deposition can be controlled by varying the parameters of the arc in the gas-plasma source.

  4. Coordination of fictive motor activity in the larval zebrafish is generated by non-segmental mechanisms.

    Directory of Open Access Journals (Sweden)

    Timothy D Wiggin

    Full Text Available The cellular and network basis for most vertebrate locomotor central pattern generators (CPGs is incompletely characterized, but organizational models based on known CPG architectures have been proposed. Segmental models propose that each spinal segment contains a circuit that controls local coordination and sends longer projections to coordinate activity between segments. Unsegmented/continuous models propose that patterned motor output is driven by gradients of neurons and synapses that do not have segmental boundaries. We tested these ideas in the larval zebrafish, an animal that swims in discrete episodes, each of which is composed of coordinated motor bursts that progress rostrocaudally and alternate from side to side. We perturbed the spinal cord using spinal transections or strychnine application and measured the effect on fictive motor output. Spinal transections eliminated episode structure, and reduced both rostrocaudal and side-to-side coordination. Preparations with fewer intact segments were more severely affected, and preparations consisting of midbody and caudal segments were more severely affected than those consisting of rostral segments. In reduced preparations with the same number of intact spinal segments, side-to-side coordination was more severely disrupted than rostrocaudal coordination. Reducing glycine receptor signaling with strychnine reversibly disrupted both rostrocaudal and side-to-side coordination in spinalized larvae without disrupting episodic structure. Both spinal transection and strychnine decreased the stability of the motor rhythm, but this effect was not causal in reducing coordination. These results are inconsistent with a segmented model of the spinal cord and are better explained by a continuous model in which motor neuron coordination is controlled by segment-spanning microcircuits.

  5. Haptic Feedback in Motor Hand Virtual Therapy Increases Precision and Generates Less Mental Workload

    Directory of Open Access Journals (Sweden)

    Cristina Ramírez-Fernández

    2015-10-01

    Full Text Available In this work we show that haptic feedback in upper limb motor therapy improves performance and generates a lower mental workload. To demonstrate this, two groups of participants (healthy adults and elders with hand motor problems used a low-cost haptic device (Novint Falcon and a non-robotic device (Leap Motion Controller. Participants conducted the same rehabilitation task by using a non-immersive virtual environment. Results show significant differences for all participants regarding precision on the use of the haptic feedback device. Additionally, participants in the older adult group demonstrated a lower mental workload while using the haptic device (Novint Falcon. Finally, qualitative results show that participants preferred to conduct their therapy exercises by using the haptic device, as they found it more useful, easier to use and easier to learn

  6. Efficient generation of ozone in arrays of microchannel plasmas

    Science.gov (United States)

    Kim, M. H.; Cho, J. H.; Ban, S. B.; Choi, R. Y.; Kwon, E. J.; Park, S.-J.; Eden, J. G.

    2013-07-01

    Ozone is produced efficiently in arrays of low-temperature, linear microplasmas having a trapezoidal or parabolic cross-sectional profile and generated within nanoporous alumina (Al2O3) microchannels. Fabricated from aluminum foil by wet chemical processing, micropowder ablation, and one photolithographic step, arrays of microchannel plasma devices 3 cm in length and 250 µm in width at the aperture of the channel produce spatially uniform glow discharges in O2 feedstock gas at a pressure of 1 atm and flow rates of 0.25-2.5 standard litres per minute. Several device and array structures, incorporating embedded electrodes and Al/Al2O3 or glass channels, have been fabricated and tested extensively. A design based solely on microchannels fabricated in nanoporous alumina, flanked by Al electrodes buried in the channel wall, is found to be superior in performance to other materials and geometries. Altering the electric field profile inside the microchannels (by means of the electrode geometry) is found to have a significant impact on the reactor efficiency. Ozone output is observed to scale linearly with the number of microchannels in the array and the feedstock gas flow rate. Efficiencies and O3 concentrations surpassing 85 g kWh-1 and 17 g m-3, respectively, have been measured, and arrays as large as 120 microchannels have been realized to date. The results presented here suggest a new approach to plasma-chemical reactors, one in which ‘massively parallel’ processing of one or more gases in non-streamer (glow) discharges efficiently produces products of commercial value in thousands of micropores or microchannels fabricated in recyclable and inexpensive materials. Reductions of an order of magnitude in the weight and volume of microplasma-based O3 reactors, relative to conventional dielectric barrier discharge technology, appear to be feasible.

  7. Terahertz generation by beating two Langmuir waves in a warm and collisional plasma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao-Bo; Qiao, Xin; Cheng, Li-Hong; Tang, Rong-An; Zhang, Ai-Xia; Xue, Ju-Kui, E-mail: xuejk@nwnu.edu.cn [Key Laboratory of Atomic & Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2015-09-15

    Terahertz (THz) radiation generated by beating of two Langmuir waves in a warm and collisional plasma is discussed theoretically. The critical angle between the two Langmuir waves and the critical wave-length (wave vector) of Langmuir waves for generating THz radiation are obtained analytically. Furthermore, the maximum radiation energy is obtained. We find that the critical angle, the critical wave-length, and the generated radiation energy strongly depend on plasma temperature and wave-length of the Langmuir waves. That is, the THz radiation generated by beating of two Langmuir waves in a warm and collisional plasma can be controlled by adjusting the plasma temperature and the Langmuir wave-length.

  8. Molecular interactions and residues involved in force generation in the T4 viral DNA packaging motor.

    Science.gov (United States)

    Migliori, Amy D; Smith, Douglas E; Arya, Gaurav

    2014-12-12

    Many viruses utilize molecular motors to package their genomes into preformed capsids. A striking feature of these motors is their ability to generate large forces to drive DNA translocation against entropic, electrostatic, and bending forces resisting DNA confinement. A model based on recently resolved structures of the bacteriophage T4 motor protein gp17 suggests that this motor generates large forces by undergoing a conformational change from an extended to a compact state. This transition is proposed to be driven by electrostatic interactions between complementarily charged residues across the interface between the N- and C-terminal domains of gp17. Here we use atomistic molecular dynamics simulations to investigate in detail the molecular interactions and residues involved in such a compaction transition of gp17. We find that although electrostatic interactions between charged residues contribute significantly to the overall free energy change of compaction, interactions mediated by the uncharged residues are equally if not more important. We identify five charged residues and six uncharged residues at the interface that play a dominant role in the compaction transition and also reveal salt bridging, van der Waals, and solvent hydrogen-bonding interactions mediated by these residues in stabilizing the compact form of gp17. The formation of a salt bridge between Glu309 and Arg494 is found to be particularly crucial, consistent with experiments showing complete abrogation in packaging upon Glu309Lys mutation. The computed contributions of several other residues are also found to correlate well with single-molecule measurements of impairments in DNA translocation activity caused by site-directed mutations.

  9. Generation of whistler mode in a relativistic plasma

    Indian Academy of Sciences (India)

    N K Deka; B J Saikia; K S Goswami

    2008-03-01

    This paper contains the plasma maser interaction between high frequency nonresonant whistler R-mode and low frequency resonant ion acoustic mode in a relativistic plasma. It shows that the whistler R-mode grows through the plasma maser interaction between the relativistic electrons and the ion acoustic fluctuation.

  10. Gallbladder motor function, plasma cholecystokinin and cholecystokinin receptor of gallbladder in cholesterol stone patients

    Institute of Scientific and Technical Information of China (English)

    Jian Zhu; Tian-Quan Han; Sheng Chen; Yu Jiang; Sheng-Dao Zhang

    2005-01-01

    AIM: To study the interactive relationship of gallbladder motor function, plasma cholecystokinin (CCK) and cholecystokinin A receptor (CCK-R) of gallbladder in patients with cholesterol stone disease.METHODS: Gallbladder motility was studied by ultrasonography in 33 patients with gallbladder stone and 10 health subjects as controls. Plasma CCK concentration was measured by radioimmunoassay in fasting status (CCK-f) and in 30 min after lipid test meal (CCK-30).Radioligand method was employed to analyze the amount and activity of CCK-R from 33 gallstone patients having cholecystectomy and 8 persons without gallstone died of severe trauma as controls.RESULTS: The percentage of cholesterol in the gallstone composition was more than 70%. The cholesterol stone type was indicated for the patients with gallbladder stone in this study. Based on the criterion of gallbladder residual fraction of the control group, 33 gallstone patients were divided into two subgroups, contractor group (14 cases)and non-contractor group (19 cases), The concentration of CCK-30 was significantly higher in non-contractor group than that in both contractor group and control group (55.86±3.86 pmol/l vs 37.85±0.88 pmol/l and 37.95±0.74 pmol/L, P<0.01), but there was no difference between contractor group and control group. Meanwhile no significant difference of the concentration of CCK-f could be observed among three groups. The amount of CCK-R was lower in non-contractor group than those in both control group and contractor group (10.27±0.94 fmol/mg vs24.59±2.39 fmol/mg and 22.66±0.55 fmol/mg, P<0.01).The activity of CCK-R shown as KD in non-contractor group decreased compared to that in control group and contractor group. Only was the activity of CCK-R lower in contractor group than that in control group. The ejection fraction correlated closely with the amount of CCK-R (r = 0.9683,P<0.01), and the concentration of CCK-30 correlated negatively with the amount of CCK-R closely (r = -0

  11. Concepts for using trapped-flux HTS in motors and generators

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R., E-mail: john.r.hull2@boeing.com [Boeing Research and Technology, PO Box 3707, Seattle, WA 98124 (United States); Strasik, Michael [Boeing Research and Technology, PO Box 3707, Seattle, WA 98124 (United States)

    2013-01-15

    Highlights: ► Use of Dy for core material increases t in situ magnetization of trapped-flux HTS. ► Hysteresis loss in Dy needs to be reduced. ► Bootstrap in situ magnetization can be done with two pulsed-power generators. -- Abstract: We examine the expected performance of a brushless motor/generator that uses trapped-flux (TF) bulk high-temperature superconductors (HTSs) to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium (Dy) for the stator and rotor cores. We also examine methods to energize TF in HTS for generators used in pulsed-power applications.

  12. Hydrogen Plasma Generation with 200 MHz RF Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeongtae; Park, Kwangmook; Seo, Dong Hyuk; Kim, Han-Sung; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The ion source for the system is required to be rugged with 2000 hours maintenance free operation time because it is installed in the vessel filled with SF6 gas at the pressure of 10 bar. A 200 MHz RF ion source is considered as an ion source. It is a simple construction and provides long life operation. The specifications of the ion source are 5 kV extraction voltage and 1 mA beam current referenced to the proton. RF ion source has been developed and undergone a performance test. Results of the test are presented. 200 MHz RF ion source is designated and manufactured. First of all test stand test of ion source are set up for a performance test of ion source. It includes a RF ion source, a 200-MHz RF system, beam extraction system, vacuum system, beam extraction system, and beam diagnostic system. At pressure of 1.2E-5 torr, hydrogen plasma is generated with net RF power 70 W. Pyrex tube surrounded by an inductive coil takes the role of vessel and discharge is enhanced with field of permanent magnets.

  13. Naphthalene and acenaphthene decomposition by electron beam generated plasma application

    Energy Technology Data Exchange (ETDEWEB)

    Ostapczuk, A.; Hakoda, T.; Shimada, A.; Kojima, T. [Institute for Nuclear Chemistry and Technology, Warsaw (Poland)

    2008-08-15

    The application of non-thermal plasma generated by electron beam (EB) was investigated in laboratory scale to study decomposition of polycyclic aromatic hydrocarbons like naphthalene and acenaphthene in flue gas. PAH compounds were treated by EB with the dose up to 8 kGy in dry and humid base gas mixtures. Experimentally established G-values gained 1.66 and 3.72 mol/100 eV for NL and AC at the dose of 1 kGy. NL and AC removal was observed in dry base gas mixtures showing that the reaction with OH radical is not exclusive pathway to initialize PAH decomposition; however in the presence of water remarkably higher decomposition efficiency was observed. As by-products of NL decomposition were identified compounds containing one aromatic ring and oxygen atoms besides CO and CO{sub 2}. It led to the conclusion that PAH decomposition process in humid flue gas can be regarded as multi-step oxidative de-aromatization analogical to its atmospheric chemistry.

  14. Arc generation from sputtering plasma-dielectric inclusion interactions

    CERN Document Server

    Wickersham, C E J; Fan, J S

    2002-01-01

    Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al sub 2 O sub 3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect...

  15. Recombination and population inversion in plasmas generated by tunneling ionization.

    Science.gov (United States)

    Pert, G J

    2006-06-01

    Above-threshold ionization (ATI) ionization by linearly polarized light has been proposed by several authors as a means of driving recombination lasers in the soft x-ray spectral region. The pump radiation generates a cold electron plasma with ions in a single ionization stage, which is an ideal starting condition for strong recombination. Population inversions form during the recombination cascade to the ground state of the next ionization stage. In the absence of any relaxation the electron distribution is strongly peaked near zero energy. However, a number of different processes all heat the cold electrons towards Maxwellian, and may thereby reduce the recombination rate in the higher levels. Using numerical models we investigate these relaxation processes and their effect on recombination. We show that the recombination can be well described by the standard cascade model, provided an appropriate temperature is used. We examine two cases in detail, hydrogen-like lithium where the inversion is with respect to the ground state, and lithium-like nitrogen where it is with the first excited state. The two cases differ markedly in the degree of relaxation achieved, and in the duration of the population inversion.

  16. Laer Pulse Driven THz Generation via Resonant Transition Radiation in Inhomogeneous Plasmas

    CERN Document Server

    Miao, Chenlong; Antonsen, Thomas M

    2016-01-01

    An intense, short laser pulse propagating across a plasma boundary ponderomotively drives THz radiation. Full format PIC simulations and theoretical analysis are conducted to investigate the properties of this radiation. Simulation results show the THz emission originates in regions of varying density and covers a broad spectrum with maximum frequency close to the maximum plasma frequency. In the case of a sharp vacuum-plasma boundary, the radiation is generated symmetrically at the plasma entrance and exit, and its properties are independent of plasma density when the density exceeds a characteristic value determined by the product of the plasma frequency and the laser pulse duration. For a diffuse vacuum-plasma boundary, the emission from the plasma entrance and exit is asymmetric: increasing and decreasing density ramps enhance and diminish the radiated energy respectively. Enhancements by factors of 50 are found and simulations show that a 1.66 J, 50 fs driver pulse can generate ~400 \\mu J of THz radiatio...

  17. Control of disruption-generated runaway plasmas in TFTR

    Science.gov (United States)

    Fredrickson, E. D.; Bell, M. G.; Taylor, G.; Medley, S. S.

    2015-01-01

    Many disruptions in the Tokamak Fusion Test Reactor (TFTR) (Meade and the TFTR Group 1991 Proc. Int. Conf. on Plasma Physics and Controlled Nuclear Fusion (Washington, DC, 1990) vol 1 (Vienna: IAEA) pp 9-24) produced populations of runaway electrons which carried a significant fraction of the original plasma current. In this paper, we describe experiments where, following a disruption of a low-beta, reversed-shear plasma, currents of up to 1 MA carried mainly by runaway electrons were controlled and then ramped down to near zero using the ohmic transformer. In the longer lasting runaway plasmas, events resembling Parail-Pogutse instabilities were observed.

  18. Generation of powerful terahertz emission in a beam-driven strong plasma turbulence

    OpenAIRE

    Arzhannikov, A.V.; Timofeev, I. V.

    2012-01-01

    Generation of terahertz electromagnetic radiation due to coalescence of upper-hybrid waves in the long-wavelength region of strong plasma turbulence driven by a high-current relativistic electron beam in a magnetized plasma is investigated. The width of frequency spectrum as well as angular characteristics of this radiation for various values of plasma density and turbulence energy are calculated using the simple theoretical model adequately describing beam-plasma experiments at mirror traps....

  19. Generation of Electrojets in Weakly Ionized Plasmas through a Collisional Dynamo

    CERN Document Server

    Dimant, Yakov S; Fletcher, Alex C

    2016-01-01

    Intense electric currents called electrojets occur in weakly ionized magnetized plasmas. An example occurs in the Earth's ionosphere near the magnetic equator where neutral winds drive the plasma across the geomagnetic field. Similar processes take place in the Solar chromosphere and MHD generators. This letter argues that not all convective neutral flows generate electrojets and it introduces the corresponding universal criterion for electrojet formation, $\

  20. Higher Plasma LDL-Cholesterol is Associated with Preserved Executive and Fine Motor Functions in Parkinson's Disease.

    Science.gov (United States)

    Sterling, Nicholas W; Lichtenstein, Maya; Lee, Eun-Young; Lewis, Mechelle M; Evans, Alicia; Eslinger, Paul J; Du, Guangwei; Gao, Xiang; Chen, Honglei; Kong, Lan; Huang, Xuemei

    2016-05-01

    Plasma low density lipoprotein (LDL) cholesterol has been associated both with risk of Parkinson's disease (PD) and with age-related changes in cognitive function. This prospective study examined the relationship between baseline plasma LDL-cholesterol and cognitive changes in PD and matched Controls. Fasting plasma LDL-cholesterol levels were obtained at baseline from 64 non-demented PD subjects (62.7 ± 7.9 y) and 64 Controls (61.3 ± 6.8 y). Subjects underwent comprehensive neuropsychological testing at baseline, 18-, and 36-months. Linear mixed-effects modeling was used to assess the relationships between baseline LDL-cholesterol levels and longitudinal cognitive changes. At baseline, PD patients had lower scores of fine motor (p0.7). The cholesterol - executive set shifting association differed significantly between PDs and Controls (interaction p=0.005), whereas the cholesterol - fine motor association difference did not reach significance (interaction, p=0.104). In summary, higher plasma LDL-cholesterol levels were associated with better executive function and fine motor performance over time in PD, both of which may reflect an effect on nigrostriatal mediation. Confirmation of these results and elucidation of involved mechanisms are warranted, and might lead to feasible therapeutic strategies.

  1. Central generation of grooming motor patterns and interlimb coordination in locusts.

    Science.gov (United States)

    Berkowitz, A; Laurent, G

    1996-12-15

    Coordinated bursts of leg motoneuron activity were evoked in locusts with deefferented legs by tactile stimulation of sites that evoke grooming behavior. This suggests that insect thoracic ganglia contain central pattern generators for directed leg movements. Motoneuron recordings were made from metathoracic and mesothoracic nerves, after eliminating all leg motor innervation, as well as all input from the brain, subesophageal ganglion, and prothoracic ganglion. Strong, brief trochanteral levator motoneuron bursts occurred, together with silence of the slow and fast trochanteral depressor motoneurons and activation of the common inhibitor motoneuron. The metathoracic slow tibial extensor motoneuron was active in a pattern distinct from its activity during walking or during rhythms evoked by the muscarinic agonist pilocarpine. Preparations in which the metathoracic ganglion was isolated from all other ganglia could still produce fictive motor patterns in response to tactile stimulation of metathoracic locations. Bursts of trochanteral levator and depressor motoneurons were clearly coordinated between the left and right metathoracic hemiganglia and also between the mesothoracic and the ipsilateral metathoracic ganglia. These data provide clear evidence for centrally generated interlimb coordination in an insect.

  2. Endogenous rhythm and pattern-generating circuit interactions in cockroach motor centres

    Directory of Open Access Journals (Sweden)

    Izhak David

    2016-09-01

    Full Text Available Cockroaches are rapid and stable runners whose gaits emerge from the intricate, and not fully resolved, interplay between endogenous oscillatory pattern-generating networks and sensory feedback that shapes their rhythmic output. Here we studied the endogenous motor output of a brainless, deafferented preparation. We monitored the pilocarpine-induced rhythmic activity of levator and depressor motor neurons in the mesothoracic and metathoracic segments in order to reveal the oscillatory networks’ architecture and interactions. Data analyses included phase relations, latencies between and overlaps of rhythmic bursts, spike frequencies, and the dependence of these parameters on cycle frequency. We found that, overall, ipsilateral connections are stronger than contralateral ones. Our findings revealed asymmetries in connectivity among the different ganglia, in which meta-to-mesothoracic ascending coupling is stronger than meso-to-metathoracic descending coupling. Within-ganglion coupling between the metathoracic hemiganglia is stronger than that in the mesothoracic ganglion. We also report differences in the role and mode of operation of homologue network units (manifested by levator and depressor nerve activity. Many observed characteristics are similar to those exhibited by intact animals, suggesting a dominant role for feedforward control in cockroach locomotion. Based on these data we posit a connectivity scheme among components of the locomotion pattern generating system.

  3. Dust generation at interaction of plasma jet with surfaces

    Science.gov (United States)

    Ticos, Catalin; Toader, Dorina; Banu, Nicoleta; Scurtu, Adrian; Oane, Mihai

    2013-10-01

    Coatings of W and C with widths of a few microns will be exposed to plasma jet for studying the erosion of the surface and detachment of micron size dust particles. A coaxial plasma gun has been built inside a vacuum chamber for producing supersonic plasma jets. Its design is based on a 50 kJ coaxial plasma gun which has been successfully used for accelerating hypervelocity dust. Initial shots were carried out for a capacitor bank with C = 12 μF and charged up to 2 kV. Currents of tens of amps were measured with a Rogowsky coil and plasma flow speeds of 4 km/s were inferred from high-speed images of jet propagation. An upgrade consisting in adding capacitors in parallel will be performed in order to increase the energy up to 2 kJ. A coil will be installed at the gun muzzle to compress the plasma flow and increase the energy density of the jet on the sample surface. A CCD camera with a maximum recording speed of 100 k fps and a maximum resolution of 1024 × 1024 pixels was set for image acquisition of the plasma and dust. A laser system used to illuminate the ejected dust from the surface includes a laser diode emitting at 650 nm with a beam power of 25 mW. The authors acknowledge support from EURATOM WP13-IPH-A03-P2-02-BS22.

  4. Generation and remote delivery of plasma activated species

    Science.gov (United States)

    Maguire, Paul; Mahony, Charles; Kelsey, Colin; Rutherford, David; Mariotti, Davide; Macias-Montero, Manuel; Perez-Martin, Fatima; Diver, Declan

    2016-09-01

    Plasma interactions with microdroplets offer new opportunities to deliver active chemical agents and nanoparticles to remote substrates downstream with many potential applications from cancer theranostics and wound healing in biomedicine, gentle food decontamination and seed germination in plasma agriculture to catalyst production and photonic structures fabrication, among others. We demonstrate plasma-liquid based pristine nanomaterials synthesis in flight and subsequent delivery up to 120mm from the atmospheric pressure plasma source. Monosized and non-aggregating metal nanoparticles are formed in the rf plasma in less than 100us, representing an increase in precursor reduction rate that is many (>4) orders of magnitude faster than that observed with standard colloidal chemistry or via high energy radiolytic techniques. Also the collection and purification limitations of the latter are avoided. Plasma activated liquid including OH radicals and H2O2 are transported over 120mm and have demonstrated high efficacy bacterial decontamination. These results will be compared with charge species and radical transport from the rf plasma without microdroplets. Reaction models based on high solvated surface electron concentrations will be presented. Funding from EPSRC acknowledged (Grants EP/K006088/1 and EP/K006142/1).

  5. Impurity generation, transport and redeposition at plasma boundary

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, M.; Ido, Y.; Ezumi, N.; Ohno, N.; Takamura, S. [Nagoya Univ. (Japan)

    1997-12-31

    Erosion and redeposition processes have been investigated using a linear plasma device and a Monte-Carlo simulation code. Molybdenum substrate is exposed to argon plasmas for oblique incidence of magnetic field under well-defined plasma conditions. The effect of magnetic field directions on the erosion distribution is clearly observed. We have a qualitative explanation for the erosion profiles with the effect of prompt redeposition of high Z material in comparison with numerical code predictions. However, we have quantitative differences for their erosion rates. (author)

  6. Atmospheric-pressure plasma jet induces apoptosis involving mitochondria via generation of free radicals.

    Directory of Open Access Journals (Sweden)

    Hak Jun Ahn

    Full Text Available The plasma jet has been proposed as a novel therapeutic method for anticancer treatment. However, its biological effects and mechanism of action remain elusive. Here, we investigated its cell death effects and underlying molecular mechanisms, using air and N₂ plasma jets from a micro nozzle array. Treatment with air or N₂ plasma jets caused apoptotic death in human cervical cancer HeLa cells, simultaneously with depolarization of mitochondrial membrane potential. In addition, the plasma jets were able to generate reactive oxygen species (ROS, which function as surrogate apoptotic signals by targeting the mitochondrial membrane potential. Antioxidants or caspase inhibitors ameliorated the apoptotic cell death induced by the air and N₂ plasma jets, suggesting that the plasma jet may generate ROS as a proapoptotic cue, thus initiating mitochondria-mediated apoptosis. Taken together, our data suggest the potential employment of plasma jets as a novel therapy for cancer.

  7. Atmospheric-pressure plasma jet induces apoptosis involving mitochondria via generation of free radicals.

    Science.gov (United States)

    Ahn, Hak Jun; Kim, Kang Il; Kim, Geunyoung; Moon, Eunpyo; Yang, Sang Sik; Lee, Jong-Soo

    2011-01-01

    The plasma jet has been proposed as a novel therapeutic method for anticancer treatment. However, its biological effects and mechanism of action remain elusive. Here, we investigated its cell death effects and underlying molecular mechanisms, using air and N₂ plasma jets from a micro nozzle array. Treatment with air or N₂ plasma jets caused apoptotic death in human cervical cancer HeLa cells, simultaneously with depolarization of mitochondrial membrane potential. In addition, the plasma jets were able to generate reactive oxygen species (ROS), which function as surrogate apoptotic signals by targeting the mitochondrial membrane potential. Antioxidants or caspase inhibitors ameliorated the apoptotic cell death induced by the air and N₂ plasma jets, suggesting that the plasma jet may generate ROS as a proapoptotic cue, thus initiating mitochondria-mediated apoptosis. Taken together, our data suggest the potential employment of plasma jets as a novel therapy for cancer.

  8. Development of Central Monitoring System for Insulation Diagnosis of High-Voltage Generator/Motor Stator Windings

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Byoung Chol; Yoon, Dae Hee; Hwang, Don Ha; Kim, Yong Joo [Mechatronics Research Group, Korea Electrotechnology Research Institute (Korea); Ju, Young Ho [Korea Electric Power Corporation (Korea); Kim, Jeong Woo [Advanced Electronic Technology Co., Ltd. (Korea)

    2000-07-01

    The central monitoring system with on-line diagnosis of high-voltage generator/motor stator insulation is developed. The system is capable of remote diagnosis and monitoring partial discharges of high-voltage generator/motor stator insulation. GOMS(Generator On-line Monitoring System) with maximum of 9 input channels can measure stator insulation by on-line. The measured and analysis data are borough to the central monitoring system via modem to build database. The central monitoring system can diagnose and monitor the insulation status of several high-voltage generator/motor at any time. The insulation status of those machines can be enhanced by the database on partial discharges. (author). 9 refs., 3 figs., 2 tabs.

  9. High density plasma gun generates plasmas at 190 kilometers per second

    Science.gov (United States)

    Espy, P. N.

    1971-01-01

    Gun has thin metal foil disc which positions or localizes gas to be ionized during electrical discharge cycle, overcoming major limiting factor in obtaining such plasmas. Expanding plasma front travels at 190 km/sec, compared to plasmas of 50 to 60 km/sec previously achieved.

  10. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Science.gov (United States)

    Lu, X.; Naidis, G. V.; Laroussi, M.; Reuter, S.; Graves, D. B.; Ostrikov, K.

    2016-05-01

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors' vision for the emerging convergence trends across several disciplines and application domains is presented to

  11. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Energy Technology Data Exchange (ETDEWEB)

    Lu, X., E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Naidis, G.V. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Laroussi, M. [Plasma Engineering & Medicine Institute, Old Dominion University, Norfolk, VA 23529 (United States); Reuter, S. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Strasse 2, 17489 Greifswald (Germany); Graves, D.B. [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States); Ostrikov, K. [Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000 (Australia); School of Physics, Chemistry, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Commonwealth Scientific and Industrial Research Organization, P.O.Box 218, Lindfield, NSW 2070 (Australia); School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-05-04

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors’ vision for the emerging convergence trends across several disciplines and application domains is presented to

  12. An efficient linear power generator - Linear motor for oscillating piston machines; Effizienter Lineargenerator / Linearmotor fuer Kolbenmaschine - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Lindegger, M.

    2008-07-01

    When an oscillating piston interacts with an electrical generator or motor, it is obvious that the electrical machine should also have linear motion, eliminating the disadvantage of a crankshaft. This work has two parts: construction of an efficient linear generator for a Stirling engine with a free piston and a theoretical study of the efficiency of linear motors for driving compressors. The Stirling engine and the linear generator have a continuous power of 1.3 kW{sub el}. With thermal peak power the planned 1.5 kW{sub el} are attained. The Project 'Stirling Free Piston Generator' for cogeneration will continue. Smaller linear motors with permanent magnets function without electronic control from single-phase AC net. The theoretical study shows how linear motors can be led out by linking the electric vector diagram with the pressure-volume diagram of the compressor. At a power level exceeding a few kW, a three-phase system with power electronics is more suitable. The frequency of oscillation is variable and lower than 50 Hz. The efficiency of the simulated linear motors lies in the range of efficiency class EFF1 of standard motors. The very high efficiencies of rotating motors with permanent magnets are not attained. The combination of the linear motor with an optimised thermal process leads to advantages regarding the efficiency. If a heat pump with linear drive system can operate with hot lubricating oil the losses in the heat exchangers are reduced. The Competence Center for Thermal Machines at Lucerne University of Applied Sciences and Arts shows great interest to pursue the project of a linear heat pump for small temperature differences. (author)

  13. High power, fast, microwave components based on beam generated plasmas

    Science.gov (United States)

    Manheimer, W. M.; Fernsler, R. F.; Gitlin, M. S.

    1998-10-01

    It is shown that the agile mirror plasma, under development as a device to simply and cheaply give electronic steering to microwave beams, also has application as a fast, electronically controlled, high power reflector, or phase shifter. In a radar system, this can lead to such applications as pulse to pulse polarization agility and electronic control of antenna gain, as well as to innovative approaches to high power millimeter wave circulators. The basic theory of the enhanced glow plasma is also developed.

  14. Studies of HED Plasmas with Self-Generated Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, Mikhail [Univ. of Kansas, Lawrence, KS (United States)

    2016-02-08

    High-amplitude sub-Larmor-scale electromagnetic turbulence is ubiquitous in high-energy density environments, such as laboratory plasmas produced by high-intensity lasers, e.g., NIF, Omega-EP, Trident, and others, and in astrophysical and space plasmas, e.g., at high-Mach-number collisionless shocks in weakly magnetized plasmas upstream regions of quasi-parallel shocks, sites of magnetic reconnection and others. Studies of plasmas and turbulence in these environments are important for fusion energy sciences and the inertial confinement concept, in particular, as well as to numerous astrophysical systems such as gamma-ray bursts, supernovae blast waves, jets of quasars and active galactic nuclei, shocks in the interplanetary medium, solar flares and many more. Such turbulence can be of various origin and thus have rather different properties, from being purely magnetic (Weibel) turbulence to various types of electromagnetic turbulence (for example, whistler wave turbulence or turbulence produced by filamentation or Weibel-type streaming instability), to purely electrostatic Langmuir turbulence. In this project we use analytical and numerical tools to study the transport, radiative, and magneto-optical properties of plasmas with sub-Larmor-scale turbulence. We discovered the connection of transport/diffusion properties to certain spectral benchmark features of (jitter) radiation produced by the plasma and radiation propagation through it. All regimes, from the relativistic to non-relativistic, were thoroughly investigated and predictions were made for laboratory plasmas and astrophysical plasmas. Thus, all the tasks outlined in the proposal were fully and successfully accomplished.

  15. Downramp-assisted underdense photocathode electron bunch generation in plasma wakefield accelerators

    CERN Document Server

    Knetsch, Alexander; Wittig, Georg; Groth, Henning; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James Benjamin; Bruhwiler, David Leslie; Smith, Johnathan; Jaroszynski, Dino Anthony; Sheng, Zheng-Ming; Manahan, Grace Gloria; Xia, Guoxing; Jamison, Steven; Hidding, Bernhard

    2014-01-01

    It is shown that the requirements for high quality electron bunch generation and trapping from an underdense photocathode in plasma wakefield accelerators can be substantially relaxed through localizing it on a plasma density downramp. This depresses the phase velocity of the accelerating electric field until the generated electrons are in phase, allowing for trapping in shallow trapping potentials. As a consequence the underdense photocathode technique is applicable by a much larger number of accelerator facilities. Furthermore, dark current generation is effectively suppressed.

  16. Numerical Study of Plasma-Fluid Behavior and Generation Characteristics of the Closed Loop MHD Electrical Power Generator

    Science.gov (United States)

    Ohno, Jun; Liberati, Alessandro; Murakami, Tomoyuki; Okuno, Yoshihiro

    Time dependent r-z two-dimensional numerical simulations with LES technique have been carried out in order to clarify the plasma fluid behavior and power generation characteristics of the disk MHD generator under the rated operation conditions demonstrated in the closed loop experimental facility at Tokyo Tech. The generator currently installed could suffer from the non-uniform and low electrical conductivity, and the boundary layer separation even under the rated operation conditions. The large amount of generated electric power is consumed in the boundary layer separation region, which reduces a net output power. Reducing the back pressure and improving the inlet plasma conditions surely provide the higher generator performance. The influence of 90 degree bend downstream duct on the generator performance is found to be not marked.

  17. Elongation of plasma channel generated by temporally shaped femtosecond laser pulse

    Science.gov (United States)

    Chen, Anmin; Li, Suyu; Qi, Hongxia; Jiang, Yuanfei; Hu, Zhan; Huang, Xuri; Jin, Mingxing

    2017-01-01

    Temporally shaped femtosecond laser pulse is used to generate the air plasma channel. The length of plasma channel is optimized by a genetic algorithm. Compared with the transform-limited pulse, the temporally shaped femtosecond laser produced by the spatial light modulator with the genetic algorithm can lead to a significant increase in length and brightness of plasma channel in atmosphere. In particular, the length of the plasma channel produced by the optimized shaped pulse can be extended by 50%. This method can be especially advantageous in the context of femtosecond laser-induced plasma channel.

  18. Control system of mutually coupled switched reluctance motor drive of mining machines in generator mode

    Science.gov (United States)

    Ivanov, A. S.; Kalanchin, I. Yu; Pugacheva, E. E.

    2017-09-01

    One of the first electric motors, based on the use of electromagnets, was a reluctance motor in the XIX century. Due to the complexities in the implementation of control system the development of switched reluctance electric machines was repeatedly initiated only in 1960 thanks to the development of computers and power electronic devices. The main feature of these machines is the capacity to work both in engine mode and in generator mode. Thanks to a simple and reliable design in which there is no winding of the rotor, commutator, permanent magnets, a reactive gate-inductor electric drive operating in the engine mode is actively being introduced into various areas such as car industry, production of household appliances, wind power engineering, as well as responsible production processes in the oil and mining industries. However, the existing shortcomings of switched reluctance electric machines, such as nonlinear pulsations of electromagnetic moment, the presence of three or four phase supply system and sensor of rotor position prevent wide distribution of this kind of electric machines.

  19. Inclined slot-excited annular electron cyclotron resonance plasma source for hyperthermal neutral beam generation.

    Science.gov (United States)

    You, H-J; Kim, D-W; Koo, M; Jang, S-O; Jung, Y-H; Hong, S-H; Lee, B-J

    2011-01-01

    An inclined slot-excited antenna (ISLAN) electron cyclotron resonance (ECR) plasma source is newly designed and constructed for higher flux hyperthermal neutral beam (HNB) generation. The developed ISLAN source is modified from vertical slot-excited antenna (VSLAN) source in two aspects: one is the use of inclined slots instead of vertical slots, and the other is a cusp magnetic field configuration rather than a toroidal configuration. Such modifications allow us to have more uniform arrangement of slots and magnets, then enabling plasma generation more uniform and thinner. Moreover, ECR plasma allows higher ionization rate, enabling plasma density higher even in submillitorr pressures, therefore decreasing the collision rate and∕or the reionization rate of the reflected atoms while passing through the plasma, and eventually getting higher flux of HNBs. In this paper, we report the design features and the plasma characteristics of the ISLAN source by doing plasma measurements and electromagnetic simulations. It was found that ISLAN source can be a high potential source for larger flux HNB generation; the source was found to give higher plasma densities and better uniformities than inductively coupled plasma source, particularly in low pressure ranges. Also, it is important that using ISLAN gives easier matching and better stability, i.e., ISLAN shows similar field patterns and good plasma symmetries irrespective of the variations of the mean diameter of the ring resonator and∕or the presence of a limiter or a reflector, and the operating pressures.

  20. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    Energy Technology Data Exchange (ETDEWEB)

    Hamaguchi, Satoshi [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-07-11

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed.

  1. Forced KLF4 expression increases the generation of mature plasma cells and uncovers a network linked with plasma cell stage.

    Science.gov (United States)

    Schoenhals, Matthieu; Jourdan, Michel; Seckinger, Anja; Pantesco, Véronique; Hose, Dirk; Kassambara, Alboukadel; Moreaux, Jérôme; Klein, Bernard

    2016-07-17

    A role of the transcription factor Krüppel-like factor 4 (KLF4) in the generation of mature plasma cells (PC) is unknown. Indeed, KLF4 is critical in controlling the differentiation of various cell linages, particularly monocytes and epithelial cells. KLF4 is expressed at low levels in pro-B cells and its expression increases as they mature into pre-B cells, resting naïve B cells and memory B cells. We show here that KLF4 is expressed in human bone marrow plasma cells and its function was studied using an in vitro model of differentiation of memory B cells into long lived plasma cells. KLF4 is rapidly lost when memory B cells differentiate into highly cell cycling plasmablasts, poorly cycling early plasma cells and then quiescent long-lived plasma cells. A forced expression of KLF4 in plasmablasts enhances the yield of their differentiation into early plasma cell and long lived plasma cells, by inhibiting apoptosis and upregulating previously unknown plasma cell pathways.

  2. An improvement in perception of self-generated tactile stimuli following theta-burst stimulation of primary motor cortex

    Science.gov (United States)

    Voss, Martin; Bays, Paul M.; Rothwell, John C.; Wolpert, Daniel M.

    2007-01-01

    Recent studies have shown that self-generated tactile sensations are perceived as weaker than the same sensations externally generated. This has been linked to a central comparator mechanism that uses efference copy to attenuate the predictable component of sensory inputs arising from one's own actions in order to enhance the salience of external stimuli. To provide a quantitative measure of this attenuation, a force-matching task was developed in which subjects experience a force applied to their finger and are then required to match the perceived force by actively pushing on the finger using their other hand. The attenuation of predictable sensory input results in subjects producing a larger active force than was experienced passively. Here, we have examined the effects of a novel rTMS protocol, theta-burst stimulation (TBS), over primary motor cortex on this attenuation. TBS can alter the excitability of motor cortex to incoming activity. We show that application of a 20 s continuous train of TBS, that depresses motor cortex, significantly improves performance in a force-matching task. This suggests that the TBS intervention disturbed the predictive process that uses efference copy signals to attenuate predictable sensory input. A possible explanation for the effect is that TBS has a differential effect on the populations of neurones that generate motor output in M1 than on those neural structures that are involved in generating an efference copy of the motor command. PMID:17560617

  3. Temporal evolution of electron beam generated Argon plasma in pasotron device

    Science.gov (United States)

    Khandelwal, Neha; Pal, U. N.; Prakash, Ram; Choyal, Y.

    2016-10-01

    The plasma- assisted slow wave oscillator (PASOTRON) is a high power microwave source in which the electron beam in the interaction region is confined by the background plasma. The plasma is generated by impact ionization of background gas with the electron beam. A model has been developed for temporal evolution of Argon plasma in pasotron device. In this model, we consider electron beam of energy E interacting with Argon gas. The resulting ionization creates quasi neutral argon plasma composed of argon Ar atoms, singly ionized ions Ar+1and electrons having energy from 0 to E. Electron impact excitation, ionization, radiative decay, radiative recombination and three body recombination processes are considered in this model. Population of ground and excited states of argon atom, ground state of argon ion as well as the population of electron energy groups is calculated by solving time dependent rate equations. Temporal evolution of electron beam generated plasma is given.

  4. Generation of high-power electromagnetic radiation by a beam-driven plasma antenna

    Science.gov (United States)

    Annenkov, V. V.; Volchok, E. P.; Timofeev, I. V.

    2016-04-01

    In this paper we study how efficiently electromagnetic radiation can be generated by a relativistic electron beam with a gigawatt power level during its injection into a thin magnetized plasma. It is shown that, if the transverse beam and plasma size is compared with the radiation wavelength and the plasma density is modulated along the magnetic field, such a beam-plasma system can radiate electromagnetic waves via the antenna mechanism. We propose a theoretical model describing generation of electromagnetic waves by this plasma antenna and calculate its main radiation characteristics. In the two-dimensional case theoretical predictions on the radiation efficiency are shown to be confirmed by the results of particle-in-cell simulations, and the three-dimensional variant of this theory is used to estimate the peak power of sub-terahertz radiation that can be achieved in beam-plasma experiments in mirror traps.

  5. High heat flux plasma generator for new divertor plasma simulator in Nagoya University

    Energy Technology Data Exchange (ETDEWEB)

    Narita, S.; Ezumi, N.; Ohno, N.; Uesugi, Y.; Takamura, S. [Nagoya Univ. (Japan)

    1997-12-31

    A new divertor simulator called NAGDIS-II has been constructed in order to investigate edge plasma physics in fusion devices. Improved TP-D type plasma source, which consists of LaB{sub 6} cathode with a Mo hollow shield and external heating system, water-cooled intermediate electrode and anode was employed to make a high density plasma in the NAGDIS-II. The performance and reliability of the discharge system was confirmed by quantitatively measuring neutral pressure, heating efficiency and plasma parameters. (author)

  6. Wakefields generated by collisional neutrinos in neutral-electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tinakiche, Nouara [Faculty of Sciences, Department of Physics, University of Boumeredes U.M.B.B., Boumerdes 35000 (Algeria)

    2015-12-15

    A classical fluid description is adopted to investigate nonlinear interaction between an electron-type neutrino beam and a relativistic collisionless unmagnetized neutral-electron-positron-ion plasma. In this work, we consider the collisions of the neutrinos with neutrals in the plasma and study their effect on the generation of wakefields in presence of a fraction of ions in a neutral-electron-positron plasma. The results obtained in the present work are interpreted and compared with previous studies.

  7. Magnetic field generation from Self-Consistent collective neutrino-plasma interactions

    Energy Technology Data Exchange (ETDEWEB)

    Brizard, A.J.; Murayama H.; Wurtele, J.S.

    1999-11-24

    A new Lagrangian formalism for self-consistent collective neutrino-plasma interactions is presented in which each neutrino species is described as a classical ideal fluid. The neutrino-plasma fluid equations are derived from a covariant relativistic variational principle in which finite-temperature effects are retained. This new formalism is then used to investigate the generation of magnetic fields and the production of magnetic helicity as a result of collective neutrino-plasma interactions.

  8. The Q motif of a viral packaging motor governs its force generation and communicates ATP recognition to DNA interaction.

    Science.gov (United States)

    Tsay, James M; Sippy, Jean; Feiss, Michael; Smith, Douglas E

    2009-08-25

    A key step in the assembly of many viruses is the packaging of DNA into preformed procapsids by an ATP-powered molecular motor. To shed light on the motor mechanism we used single-molecule optical tweezers measurements to study the effect of mutations in the large terminase subunit in bacteriophage lambda on packaging motor dynamics. A mutation, K84A, in the putative ATPase domain driving DNA translocation was found to decrease motor velocity by approximately 40% but did not change the force dependence or decrease processivity substantially. These findings support the hypothesis that a deviant "Walker A-like" phosphate-binding motif lies adjacent to residue 84. Another mutation, Y46F, was also found to decrease motor velocity by approximately 40% but also increase slipping during DNA translocation by >10-fold. These findings support the hypothesis that viral DNA packaging motors contain an adenine-binding motif that regulates ATP hydrolysis and substrate affinity analogous to the "Q motif" recently identified in DEAD-box RNA helicases. We also find impaired force generation for the Y46F mutant, which shows that the Q motif plays an important role in determining the power and efficiency of the packaging motor.

  9. Nanoparticle generation by intensified solution crystallization using cold plasma

    NARCIS (Netherlands)

    Radacsi, N.; Heijden, A.E.D.M. van der; Stankiewicz, A.I.; Horst, J.H. ter

    2013-01-01

    In this study, atmospheric pressure cold plasma (surface dielectric barrier discharge) was used as an alternative energy form to intensify solution crystallization and produce nano-sized organic crystals. Nano-sized particles can have beneficial product properties such as improved internal quality

  10. Nanoparticle generation by intensified solution crystallization using cold plasma

    NARCIS (Netherlands)

    Radacsi, N.; Heijden, A.E.D.M. van der; Stankiewicz, A.I.; Horst, J.H. ter

    2013-01-01

    In this study, atmospheric pressure cold plasma (surface dielectric barrier discharge) was used as an alternative energy form to intensify solution crystallization and produce nano-sized organic crystals. Nano-sized particles can have beneficial product properties such as improved internal quality a

  11. Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

    CERN Document Server

    Sydorenko, D; Chen, L; Ventzek, P L G

    2015-01-01

    Generation of anomalously energetic suprathermal electrons was observed in simulation of a high- voltage dc discharge with electron emission from the cathode. An electron beam produced by the emission interacts with the nonuniform plasma in the discharge via a two-stream instability. Efficient energy transfer from the beam to the plasma electrons is ensured by the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. The sheath near the anode reflects some of the accelerated electrons back into the plasma. These electrons travel through the plasma, reflect near the cathode, and enter the accelerating area again but with a higher energy than before. Such particles are accelerated to energies much higher than after the first acceleration. This mechanism plays a role in explaining earlier experimental observations of energetic suprathermal electrons i...

  12. Cold atmospheric plasma jet-generated RONS and their selective effects on normal and carcinoma cells.

    Science.gov (United States)

    Kim, Sun Ja; Chung, T H

    2016-02-03

    Cold atmospheric helium plasma jets were fabricated and utilized for plasma-cell interactions. The effect of operating parameters and jet design on the generation of specific reactive oxygen and nitrogen species (RONS) within cells and cellular response were investigated. It was found that plasma treatment induced the overproduction of RONS in various cancer cell lines selectively. The plasma under a relatively low applied voltage induced the detachment of cells, a reduction in cell viability, and apoptosis, while the plasma under higher applied voltage led to cellular necrosis in our case. To determine whether plasma-induced reactive oxygen species (ROS) generation occurs through interfering with mitochondria-related cellular response, we examined the plasma effects on ROS generation in both parental A549 cells and A549 ρ(0) cells. It was observed that cancer cells were more susceptible to plasma-induced RONS (especially nitric oxide (NO) and nitrogen dioxide (NO2(-)) radicals) than normal cells, and consequently, plasma induced apoptotic cell responses mainly in cancer cells.

  13. Generation of magnetic fields by the ponderomotive force of electromagnetic waves in dense plasmas

    OpenAIRE

    Shukla, P K; Shukla, Nitin; Stenflo, Lennart

    2010-01-01

    We show that the non-stationary ponderomotive force of a, large-amplitude electromagnetic move in a very dense quantum plasma wall streaming degenerate electrons can spontaneously create d.c. magnetic fields. The present result can account for the seed magnetic fields in compact astrophysical objects and in the next-generation intense laser-solid density, plasma interaction experiments.

  14. Generation of fast electrons by breaking of a laser-induced plasma wave

    NARCIS (Netherlands)

    Trines, Rmgm; Goloviznin, V. V.; Kamp, L. P. J.; Schep, T. J.

    2001-01-01

    A one-dimensional model for fast electron generation by an intense, nonevolving laser pulse propagating through an underdense plasma has been developed. Plasma wave breaking is considered to be the dominant mechanism behind this process, and wave breaking both in front of and behind the laser pulse

  15. Software architecture for control and data acquisition of linear plasma generator Magnum-PSI

    NARCIS (Netherlands)

    Groen, P. W. C.; van Beveren, V.; Broekema, A.; Busch, P. J.; Genuit, J. W.; Kaas, G.; Poelman, A. J.; Scholten, J.; van Emmichoven, P. A. Zeijlma

    2013-01-01

    The FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research has completed the construction phase of Magnum-PSI, a magnetized, steady-state, large area, high-flux linear plasma beam generator to study plasma surface interactions under ITER divertor conditions. Magnum-PSI consists of se

  16. Modeling and experiments on differential pumping in linear plasma generators operating at high gas flows

    NARCIS (Netherlands)

    van Eck, H. J. N.; Koppers, W. R.; van Rooij, G. J.; W. J. Goedheer,; Engeln, R.; D.C. Schram,; Cardozo, N. J. L.; Kleyn, A. W.

    2009-01-01

    The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial mag

  17. Experimental studies of axial magnetic fields generated in ultrashort-pulse laser-plasma interaction

    Institute of Scientific and Technical Information of China (English)

    李玉同; 张杰; 陈黎明; 赵理曾; 夏江帆; 魏志义; 江文勉

    2000-01-01

    The quasistatic axial magnetic fields in plasmas produced by ultrashort laser pulses were measured by measuring the Faraday rotation angle of the backscattered emission. The spatial distribution of the axial magnetic field was obtained with a peak value as high as 170 Tesla. Theory suggests that the axial magnetic field is generated by dynamo effect in laser-plasma interaction.

  18. Software architecture for control and data acquisition of linear plasma generator Magnum-PSI

    NARCIS (Netherlands)

    Groen, P. W. C.; van Beveren, V.; Broekema, A.; Busch, P. J.; Genuit, J. W.; Kaas, G.; Poelman, A. J.; Scholten, J.; van Emmichoven, P. A. Zeijlma

    2013-01-01

    The FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research has completed the construction phase of Magnum-PSI, a magnetized, steady-state, large area, high-flux linear plasma beam generator to study plasma surface interactions under ITER divertor conditions. Magnum-PSI consists of

  19. Characterization of a copper spark discharge plasma in argon atmosphere used for nanoparticle generation

    Science.gov (United States)

    Kohut, Attila; Galbács, Gábor; Márton, Zsuzsanna; Geretovszky, Zsolt

    2017-04-01

    Spark discharge nanoparticle generation is a dynamically developing application of discharge plasmas. In the present study a spark plasma used for nanoparticle generation is characterized by means of spatially and temporally resolved optical emission spectroscopy (OES) supplemented by fast imaging. The data acquired during the generation of copper nanoparticles in argon ambient is used to describe the spatial and temporal evolution of the species in the spark gap and to derive plasma parameters such as excitation temperature and electron concentration on one hand, and the concentration of the Cu species eroded by a single spark on the other. It is shown that temporally and spatially resolved OES together with a simple equilibrium model are efficient tools to estimate the characteristics of the spark discharge plasma that typically exists in spark discharge nanoparticle generators.

  20. Magnetic field generation and amplification in an expanding plasma

    CERN Document Server

    Schoeffler, K M; Fonseca, R A; Silva, L O

    2013-01-01

    Particle-in-cell simulations are used to investigate the formation of magnetic fields, B, in plasmas with perpendicular electron density and temperature gradients. For system sizes, L, comparable to the ion skin depth, d_i, it is shown that B ~ d_i/L, consistent with the Biermann battery effect. However, for large L/d_i, it is found that the Weibel instability (due to electron temperature anisotropy) supersedes the Biermann battery as the main producer of B. The Weibel-produced fields saturate at a finite amplitude (plasma \\beta \\approx 100), independent of L. The magnetic energy spectra below the electron Larmor radius scale is well fitted by power law with slope -16/3, as predicted in Schekochihin et al., Astrophys. J. Suppl. Ser 182, 310 (2009).

  1. High Magnetic field generation for laser-plasma experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Fulkerson, S; Bower, J; Satariano, J; Price, D; Glenzer, S H

    2006-05-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system suppling 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented.

  2. VUV SOURCE FROM PULSED-LASER GENERATED PLASMA

    OpenAIRE

    Laporte, P.; Damany, N.; Damany, H.

    1987-01-01

    We describe a pulsed vacuum ultraviolet (VUV) source consisting of a plasma created by focusing a NdYAG laser beam into rare gases under moderate pressure, and we report on spectral and time properties of that source. Main features are : continuum emission in a large spectral range, with only few lines superimposed, good time characteristics of the pulses, stability, cleanliness, and relatively high repetition rate (20 Hz).

  3. Optical Characterization of Plasma Generated in a Commercial Grade Plasma Etching System

    Science.gov (United States)

    Hardy, Ashley; Drake, Dereth

    2015-11-01

    The use of plasma for etching and cleaning of many types of metal surfaces is becoming more prominent in industry. This is primarily due to the fact that plasma etching can reduce the amount of time necessary to clean/etch the surface and does not require large amounts of environmentally hazardous chemicals. Most plasma etching systems are designed and built in academic institutions. These systems provide reasonable etching rates and easy accessibility for monitoring plasma parameters. The downside is that the cost is typically high. Recently a number of commercial grade plasma etchers have been introduced on the market. These etching systems cost near a fraction of the price, making them a more economical choice for researchers in the field. However, very few academics use these devices because their effectiveness has not yet been adequately verified in the current literature. We will present the results from experiments performed in a commercial grade plasma etching system, including analysis of the pulse characteristics observed by a photo diode and the plasma parameters obtained with optical emission spectroscopy.

  4. Application of Super-Synchronization Speed Control Technology in Two 80 MVA Motor-Generator Units of HL-2A

    Science.gov (United States)

    Li, Huajun; Du, Chang; Xuan, Weiming; Pen, Jianfei; Hu, Haotian; Liu, Lin; Kang, Li; Xu, Lirong; Huang, Zhaorong; Wang, Fen; Wang, Xiaoping

    2007-04-01

    Two sets of super-synchronization speed control assemblies for two 80 MVA motor-generator units have been developed successfully in order to satisfy the demand of the toroidal field system in the HL-2A tokamak. Based on the three-phase logical no-circumfluence a.c./a.c. cycloconverter, the speeds of two 2500 kW double fed drive motors have been regulated by means of the vector control technology. The maximum operating speed of each motor- generator unit has been raised from 1488 rpm (revolutions per minute) to 1650 rpm and the released energy of each unit during a pulsed discharge can reach 500 MJ. As a result, the toroidal field system has the capacity to provide 2.8 tesla (T) in HL-2A experiments.

  5. Optimized plasma high harmonics generation from ultra-intense laser pulses

    CERN Document Server

    Tang, Suo; Keitel, Christoph H

    2016-01-01

    Plasma high harmonics generation from extremely intense short-pulse laser is explored by including the effects of ion motion and radiation reaction force in the plasma dynamics. The laser radiation pressure induces plasma ion motion through the hole-boring effect resulting into the frequency shifting and widening of the harmonic spectra thereby constraining the coherence properties of the harmonics. Radiation reaction force slightly mitigates the effects caused by the ion motion. Based on the analytical estimates and particle-in-cell simulation results, an optimum parameter regime of plasma high-harmonics is presented.

  6. High-temperature coal-syngas plasma characteristics for advanced MHD power generation

    Energy Technology Data Exchange (ETDEWEB)

    Mikheev, A.V.; Kayukawa, N.; Okinaka, N.; Kamada, Y.; Yatsu, S. [Hokkaido University, Hokkaido (Japan)

    2006-03-15

    Properties of magnetohydrodynamic (MHD) plasma based on syngas (CO, H{sub 2}) combustion products were investigated experimentally with shock tube facility. The experiments were carried out under various MHD generator load and shock tube operation conditions. Important characteristics of syngas plasma such as temperature, electric field, conductivity, and total output power were directly measured and evaluated. Special attention was paid to the influence of syngas composition (CO : H{sub 2} : O{sub 2} ratio). The results show that syngas combustion can provide high plasma ionization and attainable plasma electrical conductivity has an order of 60-80 S/m at gas temperature 3100-3300 K.

  7. Targeting cancer cells with reactive oxygen and nitrogen species generated by atmospheric-pressure air plasma.

    Directory of Open Access Journals (Sweden)

    Hak Jun Ahn

    Full Text Available The plasma jet has been proposed as a novel therapeutic method for cancer. Anticancer activity of plasma has been reported to involve mitochondrial dysfunction. However, what constituents generated by plasma is linked to this anticancer process and its mechanism of action remain unclear. Here, we report that the therapeutic effects of air plasma result from generation of reactive oxygen/nitrogen species (ROS/RNS including H2O2, Ox, OH-, •O2, NOx, leading to depolarization of mitochondrial membrane potential and mitochondrial ROS accumulation. Simultaneously, ROS/RNS activate c-Jun NH2-terminal kinase (JNK and p38 kinase. As a consequence, treatment with air plasma jets induces apoptotic death in human cervical cancer HeLa cells. Pretreatment of the cells with antioxidants, JNK and p38 inhibitors, or JNK and p38 siRNA abrogates the depolarization of mitochondrial membrane potential and impairs the air plasma-induced apoptotic cell death, suggesting that the ROS/RNS generated by plasma trigger signaling pathways involving JNK and p38 and promote mitochondrial perturbation, leading to apoptosis. Therefore, administration of air plasma may be a feasible strategy to eliminate cancer cells.

  8. Computer Model for Electrode Plasma Generation by Electron and Ion Flows

    Science.gov (United States)

    Ryzhov, Victor V.; Bespalov, Valeri I.; Kirikov, Alexander V.; Turchanovskii, Igor. Yu.; Tarakanov, Vladimir P.

    2002-12-01

    A model is proposed for computer simulation of the electrode plasma generation by electron and ion flows. The distribution of the absorbed energy of particles in the electrode material is calculated by the Monte-Carlo codes. This provides a possibility to control the electrode temperature by solving the heat conductivity equation for specified distributions of thermal sources and to calculate the rate of plasma generation. The behavior of the plasma in the gap can be modeled based on simple model where the velocity, the density, and the temperature of the plasma can be given by some dependence. Within the framework of the model proposed, numerical study is performed on the effect of the plasma flows in Rod Pinch Diodes and in the Insulator Stack of the Z-accelerator.

  9. Negative-permittivity plasma generation in negative-permeability space with high-energy metamaterials

    Science.gov (United States)

    Sakai, Osamu; Nakamura, Yoshihiro; Iwai, Akinori; Iio, Satoshi

    2016-10-01

    Plasma generation by electromagnetic waves in negative-permeability space is analyzed using experimental results and theoretical models. Installation of negative-permeability metamaterials triggers drastic changes to the propagation of electromagnetic waves. Unlike usual cases in which permeability is  +1, negative permeability induces evanescent modes in a space without plasma. However, if permittivity becomes negative due to high-electron-density or overdense plasma, electromagnetic waves can propagate because negative-refractive-index states emerge. In this study, reviewing our previous experimental data, we study the underlying physical processes in plasma generation in terms of wave propagation and parameters of wave media. We confirm nonlinear (transition) processes in the phase of density evolution up to the negative permittivity state and negative-refractive-index states in the quasi-steady phase. We also note that such energetic metamaterials are built up when we use plasma, unlike conventional metamaterials composed of solid-state materials.

  10. Effects of cold atmospheric plasma generated in DI water on Cancer cells

    CERN Document Server

    Chen, Zhitong; Cheng, Xiaoqian; Gjika, Eda; Keidar, Michael

    2016-01-01

    Cold atmospheric plasma (CAP) has been shown to affect cells not only directly, but also by means of indirect treatment with previously prepared plasma stimulated solution. The objective of this study is to reveal the effects of plasma-stimulated media (PSM) on breast cancer cells (MDA-MB-231) and gastric cancer cells (NCl-N87). In our experiments, cold atmospheric plasma is generated in water using helium as carrier gas. The plasma generated in DI water during a 30-minute treatment had the strongest affect in inducing apoptosis in cultured human breast and gastric cancer cells. This result can be attributed to the presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced in water during treatment.

  11. Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

    Science.gov (United States)

    Whalley, Richard D.; Walsh, James L.

    2016-08-01

    Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence.

  12. Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device.

    Science.gov (United States)

    Whalley, Richard D; Walsh, James L

    2016-08-26

    Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence.

  13. Operational characteristics of the high flux plasma generator Magnum-PSI

    Energy Technology Data Exchange (ETDEWEB)

    Eck, H.J.N. van, E-mail: h.j.n.vaneck@differ.nl [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Abrams, T. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Berg, M.A. van den; Brons, S.; Eden, G.G. van [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Jaworski, M.A.; Kaita, R. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Meiden, H.J. van der; Morgan, T.W.; Pol, M.J. van de; Scholten, J.; Smeets, P.H.M.; De Temmerman, G.; Vries, P.C. de; Zeijlmans van Emmichoven, P.A. [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

    2014-10-15

    Highlights: •We have described the design and capabilities of the plasma experiment Magnum-PSI. •The plasma conditions are well suited for PSI studies in support of ITER. •Quasi steady state heat fluxes over 10 MW m{sup −2} have been achieved. •Transient heat and particle loads can be generated to simulate ELM instabilities. •Lithium coating can be applied to the surfaces of samples under vacuum. -- Abstract: In Magnum-PSI (MAgnetized plasma Generator and NUMerical modeling for Plasma Surface Interactions), the high density, low temperature plasma of a wall stabilized dc cascaded arc is confined to a magnetized plasma beam by a quasi-steady state axial magnetic field up to 1.3 T. It aims at conditions that enable fundamental studies of plasma–surface interactions in the regime relevant for fusion reactors such as ITER: 10{sup 23}–10{sup 25} m{sup −2} s{sup −1} hydrogen plasma flux densities at 1–5 eV. To study the effects of transient heat loads on a plasma-facing surface, a high power pulsed magnetized arc discharge has been developed. Additionally, the target surface can be transiently heated with a pulsed laser system during plasma exposure. In this contribution, the current status, capabilities and performance of Magnum-PSI are presented.

  14. Cellular basis for singing motor pattern generation in the field cricket (Gryllus bimaculatus DeGeer)

    Science.gov (United States)

    Schöneich, Stefan; Hedwig, Berthold

    2012-01-01

    The singing behavior of male crickets allows analyzing a central pattern generator (CPG) that was shaped by sexual selection for reliable production of species-specific communication signals. After localizing the essential ganglia for singing in Gryllus bimaculatus, we now studied the calling song CPG at the cellular level. Fictive singing was initiated by pharmacological brain stimulation. The motor pattern underlying syllables and chirps was recorded as alternating spike bursts of wing-opener and wing-closer motoneurons in a truncated wing nerve; it precisely reflected the natural calling song. During fictive singing, we intracellularly recorded and stained interneurons in thoracic and abdominal ganglia and tested their impact on the song pattern by intracellular current injections. We identified three interneurons of the metathoracic and first unfused abdominal ganglion that rhythmically de- and hyperpolarized in phase with the syllable pattern and spiked strictly before the wing-opener motoneurons. Depolarizing current injection in two of these opener interneurons caused additional rhythmic singing activity, which reliably reset the ongoing chirp rhythm. The closely intermeshing arborizations of the singing interneurons revealed the dorsal midline neuropiles of the metathoracic and three most anterior abdominal neuromeres as the anatomical location of singing pattern generation. In the same neuropiles, we also recorded several closer interneurons that rhythmically hyper- and depolarized in the syllable rhythm and spiked strictly before the wing-closer motoneurons. Some of them received pronounced inhibition at the beginning of each chirp. Hyperpolarizing current injection in the dendrite revealed postinhibitory rebound depolarization as one functional mechanism of central pattern generation in singing crickets. PMID:23170234

  15. Electron beam generated whistler emissions in a laboratory plasma

    Energy Technology Data Exchange (ETDEWEB)

    Van Compernolle, B., E-mail: bvcomper@physics.ucla.edu; Pribyl, P.; Gekelman, W. [Department of Physics, University of California, Los Angeles (United States); An, X.; Bortnik, J.; Thorne, R. M. [Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles (United States)

    2015-12-10

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  16. Electron beam generated whistler emissions in a laboratory plasma

    Science.gov (United States)

    Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.

    2015-12-01

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  17. Helium generated cold plasma finely regulates activation of human fibroblast-like primary cells.

    Directory of Open Access Journals (Sweden)

    Paola Brun

    Full Text Available Non-thermal atmospheric pressure plasmas are being developed for a wide range of health care applications, including wound healing. However in order to exploit the potential of plasma for clinical applications, the understanding of the mechanisms involved in plasma-induced activation of fibroblasts, the cells active in the healing process, is mandatory. In this study, the role of helium generated plasma in the tissue repairing process was investigated in cultured human fibroblast-like primary cells, and specifically in hepatic stellate cells and intestinal subepithelial myofibroblasts. Five minutes after treatment, plasma induced formation of reactive oxygen species (ROS in cultured cells, as assessed by flow cytometric analysis of fluorescence-activated 2',7'-dichlorofluorescein diacetate probe. Plasma-induced intracellular ROS were characterized by lower concentrations and shorter half-lives with respect to hydrogen peroxide-induced ROS. Moreover ROS generated by plasma treatment increased the expression of peroxisome proliferator activated receptor (PPAR-γ, nuclear receptor that modulates the inflammatory responses. Plasma exposure promoted wound healing in an in vitro model and induced fibroblast migration and proliferation, as demonstrated, respectively, by trans-well assay and partitioning between daughter cells of carboxyfluorescein diacetate succinimidyl ester fluorescent dye. Plasma-induced fibroblast migration and proliferation were found to be ROS-dependent as cellular incubation with antioxidant agents (e.g. N-acetyl L-cysteine cancelled the biological effects. This study provides evidence that helium generated plasma promotes proliferation and migration in liver and intestinal fibroblast-like primary cells mainly by increasing intracellular ROS levels. Since plasma-evoked ROS are time-restricted and elicit the PPAR-γ anti-inflammatory molecular pathway, this strategy ensures precise regulation of human fibroblast activation and

  18. Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

    Science.gov (United States)

    Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

    2017-04-01

    We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

  19. Basic characteristics of an atmospheric pressure rf generated plasma jet

    Institute of Scientific and Technical Information of China (English)

    Wang Shou-Guo; Li Hai-Jiang; Ye Tian-Chun; Zhao Ling-Li

    2004-01-01

    A plasma jet has been developed which operates using radio frequency (rf) power and produces a stable homogeneous discharge at atmospheric pressure. Its discharge characteristics, especially the dependence of stable discharge operating range on the feed gas, were studied, and the electric parameters such as RMS current, RMS voltage and reflected power were obtained with different gas flows. These studies indicate that there is an optimum range of operation of the plasma jet for a filling with a gas mixture of He and O2. Two "failure" modes of the discharge are identified.One is a filamentary arc when the input power is raised above a critical level, another is that the discharge disappears gradually as the addition of O2 approaches 3.2%. Possible explanations for the two failure modes have been given. The current and voltage waveform measurements show that there is a clear phase shift between normal and failure modes.In addition, Ⅰ-Ⅴ curves as a function of pure helium and for 1% addition of oxygen have been studied.

  20. Simulation of runaway electron generation during plasma shutdown by impurity injection

    Energy Technology Data Exchange (ETDEWEB)

    Feher, Tamas

    2011-03-15

    Disruptions are dangerous instabilities in tokamaks that should be avoided or mitigated. One possible disruption mitigation method is to inject impurities into the plasma to shut it down in a controlled way. Runaway Electrons (REs) can be generated after the plasma is cooled down by the impurities and these electrons can damage the tokamak. In this work a simulation code is developed to investigate different disruption mitigation scenarios. The response of the bulk plasma, more precisely the temperature evolution of electrons, deuterium and impurity ions are described by energy balance equations in a 1D cylindrical plasma model. The induction and resistive diffusion of electric field is calculated. RE generation rates are used to calculate the runaway current. The Dreicer, hot-tail and avalanche effect is taken into account and a simple model for RE losses is also included. RE generation is studied in JET-like plasmas during pellet injection. Carbon pellets cause effective cooling but these scenarios are prone to runaway generation. A mixture of argon and deuterium gas could be used for safe shutdown without RE generation. In ITER the hot-tail RE generation process becomes important, and the simulation is therefore extended to take this into account. Shutdown scenarios with different concentration of neon and argon impurities were tested in ITER-like plasmas. To simplify the problem the impurity injection into the plasma is not modeled in these cases, only the response of the bulk plasma. The avalanche process cannot be suppressed in a simple way and would produce high runaway current. It can be avoided if some runaway loss phenomenon is included in the simulations, like diffusion due to magnetic perturbations

  1. A simplified analytic form for generation of axisymmetric plasma boundaries

    Science.gov (United States)

    Luce, T. C.

    2017-04-01

    An improved method has been formulated for generating analytic boundary shapes as input for axisymmetric MHD equilibria. This method uses the family of superellipses as the basis function, as previously introduced. The improvements are a simplified notation, reduction of the number of simultaneous nonlinear equations to be solved, and the realization that not all combinations of input parameters admit a solution to the nonlinear constraint equations. The method tests for the existence of a self-consistent solution and, when no solution exists, it uses a deterministic method to find a nearby solution. Examples of generation of boundaries, including tests with an equilibrium solver, are given.

  2. The Generation of Magnetic Field by Transverse Plasmons in Laser-Produced Plasma

    Institute of Scientific and Technical Information of China (English)

    LIU Shan-qiu; LI Xiao-qing

    2000-01-01

    In this paper, it is studied that a quasi-steady magnetic field could be generated in laser-producde plasmas with high-frequency electromagnetic radiation through wave-wave and wave-partide interactions in the vicinity of critical point. The behavior of self-generated magnetic field can be described by nonlinear coupling equatiom.

  3. Generation of high-field narrowband terahertz radiation by counterpropagating plasma wakefields

    Science.gov (United States)

    Timofeev, I. V.; Annenkov, V. V.; Volchok, E. P.

    2017-10-01

    It is found that nonlinear interaction of plasma wakefields driven by counterpropagating laser or particle beams can efficiently generate high-power electromagnetic radiation at the second harmonic of the plasma frequency. Using a simple analytical theory and particle-in-cell simulations, we show that this phenomenon can be attractive for producing high-field ( ˜10 MV/cm) tunable terahertz radiation with a narrow line width. For laser drivers produced by existing petawatt-class systems, this nonlinear process opens the way to the generation of gigawatt, multi-millijoule terahertz pulses which are not presently available for any other generating schemes.

  4. Spatial properties of a terahertz beam generated from a two-color air plasma

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Wang, Tianwu; Buron, Jonas Christian Due

    2013-01-01

    We present a spatial characterization of terahertz (THz) beams generated from a two-color air plasma under different conditions by measuring full 3D beam profiles using a commercial THz camera. We compare two THz beam profiles emitted from plasmas generated by 35 fs and 100 fs laser pulses......, and show that the spatial properties of the two THz beams do not change significantly. For the THz beam profile generated by the 35 fs pulse, the spatial effect of eliminating the lower frequencies is investigated by implementing two crossed polarizers working as a high-pass filter. We show...

  5. Development of a new atmospheric pressure cold plasma jet generator and application in sterilization

    Institute of Scientific and Technical Information of China (English)

    Cheng Cheng; Liu Peng; Xu Lei; Zhang Li-Ye; Zhan Ru-Juan; Zhang Wen-Rui

    2006-01-01

    This paper reports that a new plasma generator at atmospheric pressure, which is composed of two homocentric cylindrical all-metal tubes, successfully generates a cold plasma jet. The inside tube electrode is connected to ground,the outside tube electrode is connected to a high-voltage power supply, and a dielectric layer is covered on the outside tube electrode. When the reactor is operated by low-frequency (6 kHz-20 kHz) AC supply in atmospheric pressure and argon is steadily fed as a discharge gas through inside tube electrode, a cold plasma jet is blown out into air and the plasma gas temperature is only 25-30 ℃. The electric character of the discharge is studied by using digital real-time oscilloscope (TDS 200-Series), and the discharge is capacitive. Preliminary results are presented on the decontamination of E.colis bacteria and Bacillus subtilis bacteria by this plasma jet, and an optical emission analysis of the plasma jet is presented in this paper. The ozone concentration generated by the plasma jet is 1.0 × 1016cm-3 which is acquired by using the ultraviolet absorption spectroscopy.

  6. Generation of zonal flows in rotating fluids and magnetized plasmas

    DEFF Research Database (Denmark)

    Juul Rasmussen, J.; Garcia, O.E.; Naulin, V.

    2006-01-01

    contribution the generation of zonal flows will be illustrated in a simple fluid experiment performed in a rotating container with radial symmetric bottom topography. An effective mixing that homogenizes the potential vorticity in the fluid layer will lead to the replacement of the high-potential vorticity...

  7. New approaches for the reduction of plasma arc drop in second-generation thermionic converters

    Science.gov (United States)

    Hatziprokopiou, M. E.; Shaw, D. T.

    1981-03-01

    Investigations of ion generation and recombination mechanisms in the cesium plasma are described with respect to the advanced mode thermionic energy converter. The changes in plasma density and temperature within the converter were studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation were studied in some detail, namely vibrationally excited N2 as an energy source of ionization of Cs ions in a dc discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N2-Cs mixture. The data obtained show that all three techniques - i.e., the non-LTE high voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

  8. Self-consistent modeling of radio-frequency plasma generation in stellarators

    Science.gov (United States)

    Moiseenko, V. E.; Stadnik, Yu. S.; Lysoivan, A. I.; Korovin, V. B.

    2013-11-01

    A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell's equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell's equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell's equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell's equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

  9. Fast camera studies at an electron cyclotron resonance table plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Rácz, R., E-mail: rracz@atomki.hu [Institute for Nuclear Research (ATOMKI), H-4026 Debrecen, Bem tér 18/c (Hungary); Department of Experimental Physics, University of Debrecen, H-4032 Debrecen, Egyetem tér 1 (Hungary); Biri, S. [Institute for Nuclear Research (ATOMKI), H-4026 Debrecen, Bem tér 18/c (Hungary); Hajdu, P.; Pálinkás, J. [Department of Experimental Physics, University of Debrecen, H-4032 Debrecen, Egyetem tér 1 (Hungary)

    2014-02-15

    A simple table-size ECR plasma generator operates in the ATOMKI without axial magnetic trap and without any particle extraction tool. Radial plasma confinement is ensured by a NdFeB hexapole. The table-top ECR is a simplified version of the 14 GHz ATOMKI-ECRIS. Plasma diagnostics experiments are planned to be performed at this device before installing the measurement setting at the “big” ECRIS. Recently, the plasma generator has been operated in pulsed RF mode in order to investigate the time evolution of the ECR plasma in two different ways. (1) The visible light radiation emitted by the plasma was investigated by the frames of a fast camera images with 1 ms temporal resolution. Since the visible light photographs are in strong correlation with the two-dimensional spatial distribution of the cold electron components of the plasma it can be important to understand better the transient processes just after the breakdown and just after the glow. (2) The time-resolved ion current on a specially shaped electrode was measured simultaneously in order to compare it with the visible light photographs. The response of the plasma was detected by changing some external setting parameters (gas pressure and microwave power) and was described in this paper.

  10. Generation Control of ZnO Nanoparticles Using a Coaxial Gas-Flow Pulse Plasma Ar/O2 Plasma

    Directory of Open Access Journals (Sweden)

    Hiroki Shirahata

    2015-01-01

    Full Text Available Generation of ZnO nanoparticles was investigated using a coaxial gas-flow pulse plasma. We studied how zinc atoms, sputtered from a zinc target, reacted with oxygen in a plasma and/or on a substrate to form ZnO nanoparticles when the discharge parameters, such as applied pulse voltage and gas flow rate, were controlled in an O2/Ar plasma. The formation processes were estimated by SEM, TEM, and EDX. We observed many ZnO nanoparticles deposited on Si substrate. The particle yield and size were found to be controlled by changing the experimental parameters. The diameter of the particles was typically 50–200 nm.

  11. Optical emission spectroscopy of the Linac4 and superconducting proton Linac plasma generators

    Energy Technology Data Exchange (ETDEWEB)

    Lettry, J.; Kronberger, M.; Mahner, E.; Schmitzer, C.; Sanchez, J.; Scrivens, R.; Midttun, O.; O' Neil, M.; Pereira, H.; Paoluzzi, M. [European Organization for Nuclear Research, CERN, 1211 Geneva 23 (Switzerland); Fantz, U.; Wuenderlich, D. [Max-Planck-Institut fuer Plasmaphysik, IPP, 85748 Garching (Germany); Kalvas, T.; Koivisto, H.; Komppula, J.; Myllyperkioe, P.; Tarvainen, O. [Department of Physics, University of Jyvaeskylae, 40500 Jyvaeskylae (Finland)

    2012-02-15

    CERN's superconducting proton Linac (SPL) study investigates a 50 Hz high-energy, high-power Linac for H{sup -} ions. The SPL plasma generator is an evolution of the DESY ion source plasma generator currently operated at CERN's Linac4 test stand. The plasma generator is a step towards a particle source for the SPL, it is designed to handle 100 kW peak RF-power at a 6% duty factor. While the acquisition of an integrated hydrogen plasma optical spectrum is straightforward, the measurement of a time-resolved spectrum requires dedicated amplification schemes. The experimental setup for visible light based on photomultipliers and narrow bandwidth filters and the UV spectrometer setup are described. The H{sub {alpha}}, H{sub {beta}}, and H{sub {gamma}} Balmer line intensities, the Lyman band and alpha transition were measured. A parametric study of the optical emission from the Linac4 ion source and the SPL plasma generator as a function of RF-power and gas pressure is presented. The potential of optical emission spectrometry coupled to RF-power coupling measurements for on-line monitoring of short RF heated hydrogen plasma pulses is discussed.

  12. A 3-dimensional model for inductively coupled plasma etching reactors: Coil generated plasma asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Kushner, M.J.; Collison, W.Z.; Grapperhaus, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1996-12-31

    Inductively Coupled Plasma (ICP) reactors are being developed as high plasma density, low gas pressure sources for etching and deposition of semiconductor materials. In this paper, the authors describe a 3-dimensional, time dependent model for ICP reactors whose intent is to provide an infrastructure to investigate asymmetries in plasma etching and deposition tools. The model is a 3-dimensional extension of a previously described 2-dimensional simulation called the Hybrid Plasma Equipment Model (HPEM). HPEM-3D consists of an electromagnetics module (EMM), a Boltzmann-electron energy module (BEM) and a fluid-chemical kinetics simulation (FKS). The inductively coupled electromagnetic fields are produced by the EMM. Results from HPEM-3D will be discussed for reactors using etching (Cl{sub 2}, BCl{sub 3}) and non-etching (Ar, Ar/N{sub 2}) gas mixtures, and which have geometrical asymmetries such as wafer clamps and load-lock bays. The authors show how details in the design of the coil, such as the value of the termination capacitance or number of turns, lead to azimuthal variations in the inductive electric field.

  13. Plasma characterization of the superconducting proton linear accelerator plasma generator using a 2 MHz compensated Langmuir probe.

    Science.gov (United States)

    Schmitzer, C; Kronberger, M; Lettry, J; Sanchez-Arias, J; Störi, H

    2012-02-01

    The CERN study for a superconducting proton Linac (SPL) investigates the design of a pulsed 5 GeV Linac operating at 50 Hz. As a first step towards a future SPL H(-) volume ion source, a plasma generator capable of operating at Linac4 or nominal SPL settings has been developed and operated at a dedicated test stand. The hydrogen plasma is heated by an inductively coupled RF discharge e(-) and ions are confined by a magnetic multipole cusp field similar to the currently commissioned Linac4 H(-) ion source. Time-resolved measurements of the plasma potential, temperature, and electron energy distribution function obtained by means of a RF compensated Langmuir probe along the axis of the plasma generator are presented. The influence of the main tuning parameters, such as RF power and frequency and the timing scheme is discussed with the aim to correlate them to optimum H(-) ion beam parameters measured on an ion source test stand. The effects of hydrogen injection settings which allow operation at 50 Hz repetition rate are discussed.

  14. Two-Color Laser High-Harmonic Generation in Cavitated Plasma Wakefields

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

    2016-10-03

    A method is proposed for producing coherent x-rays via high-harmonic generation using a laser interacting with highly-stripped ions in cavitated plasma wakefields. Two laser pulses of different colors are employed: a long-wavelength pulse for cavitation and a short-wavelength pulse for harmonic generation. This method enables efficient laser harmonic generation in the sub-nm wavelength regime.

  15. High Power, Solid-State RF Generation for Plasma Heating

    Science.gov (United States)

    Prager, James; Ziemba, Timothy; Miller, Kenneth; Pierren, Chris

    2016-10-01

    Radio Frequency heating systems are rarely used by the small-scale validation platform experiments due to the high cost and complexity of these systems. Eagle Harbor Technologies (EHT), Inc. is developing an all-solid-state RF plasma heating system that uses EHT's nanosecond pulser technology in an inductive adder configuration to drive nonlinear transmission lines (NLTL). The system under development does not require the use of vacuum tube technology, is inherently lower cost, and is more robust than traditional high power RF heating schemes. The inductive adder can produce 0 to20 kV pulses into 50 Ohms with sub-10 ns rise times. The inductive adder has been used to drive NLTLs near 2 GHz with other frequencies to be tested in the future. EHT will present experimental results, including RF measurements with D-dot probes and capacitve voltage probes. During this program, EHT will test the system on Helicity Injected Torus at the University of Washington and the High Beta Tokamak at Columbia University.

  16. Plasma wave and third harmonic generation by a Gaussian electromagnetic beam in a collisionless magnetoplasma

    Energy Technology Data Exchange (ETDEWEB)

    Sodha, M.S.; Govind; Sharma, R.P. (Indian Inst. of Tech., New Delhi. Centre of Energy Studies)

    1981-05-01

    An investigation of the plasma wave and third harmonic generation by a Gaussian electromagnetic (em) beam, propagating in extraordinary mode in a collisionless hot magnetoplasma has been made. On account of the (VXB) force, a plasma wave at twice the pump wave frequency gets excited. The interaction of the plasma wave with the pump wave leads to third harmonic generation. By taking into account the self-focusing of the pump wave on account of non-uniform intensity distribution along the wave front, a modification is effected in the power of the plasma wave and the third harmonic em wave. The dependence of these phenomena on the strength of the static magnetic field has also been studied.

  17. Second harmonic generation of Cosh-Gaussian laser beam in collisional plasma with nonlinear absorption

    Science.gov (United States)

    Singh, Navpreet; Gupta, Naveen; Singh, Arvinder

    2016-12-01

    This paper investigates second harmonic generation (SHG) of an intense Cosh-Gaussian (ChG) laser beam propagating through a preformed underdense collisional plasma with nonlinear absorption. Nonuniform heating of plasma electrons takes place due to the nonuniform irradiance of intensity along the wavefront of laser beam. This nonuniform heating of plasma leads to the self-focusing of the laser beam and thus produces strong density gradients in the transverse direction. The density gradients so generated excite an electron plasma wave (EPW) at pump frequency that interacts with the pump beam to produce its second harmonics. To envision the propagation dynamics of the ChG laser beam, moment theory in Wentzel-Kramers-Brillouin (W.K.B) approximation has been invoked. The effects of nonlinear absorption on self-focusing of the laser beam as well as on the conversion efficiency of its second harmonics have been theoretically investigated.

  18. A differentially pumped argon plasma in the linear plasma generator Magnum-PSI: gas flow and dynamics of the ionized fraction

    NARCIS (Netherlands)

    van Eck, H. J. N.; Hansen, T. A. R.; Kleyn, A. W.; van der Meiden, H. J.; D.C. Schram,; van Emmichoven, P. A. Zeijlma

    2011-01-01

    Magnum-PSI is a linear plasma generator designed to reach the plasma-surface interaction (PSI) regime of ITER and nuclear fusion reactors beyond ITER. To reach this regime, the influx of cold neutrals from the source must be significantly lower than the plasma flux reaching the target. This is

  19. A differentially pumped argon plasma in the linear plasma generator Magnum-PSI: gas flow and dynamics of the ionized fraction

    NARCIS (Netherlands)

    van Eck, H. J. N.; Hansen, T. A. R.; Kleyn, A. W.; van der Meiden, H. J.; D.C. Schram,; van Emmichoven, P. A. Zeijlma

    2011-01-01

    Magnum-PSI is a linear plasma generator designed to reach the plasma-surface interaction (PSI) regime of ITER and nuclear fusion reactors beyond ITER. To reach this regime, the influx of cold neutrals from the source must be significantly lower than the plasma flux reaching the target. This is achie

  20. Thermal Performance of Motor and Inverter in an Integrated Starter Generator System for a Hybrid Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Sung Chul Kim

    2013-11-01

    Full Text Available If the integrated starter generator (ISG motor and inverter operate under continuously high loading conditions, the system’s performance and durability will decrease and the heat dissipation requirements will increase. Therefore, in this study, we developed two cooling designs for the ISG motor and inverter, and then carried out both a model analysis and an experiment on the fluid flow and thermal characteristics of the system under various operating conditions. As the outdoor temperature increased from 25 °C to 95 °C, the coil temperature of the air-cooled motor increased by about 82 °C. Under the harsh-air condition of 95 °C, the coil of the air-cooled motor increased to a maximum temperature of about 158.5 °C. We also determined that the temperature of the metal-oxide-semiconductor field-effect transistor (MOSFET chip in the liquid-cooled inverter increased to a maximum temperature of about 96.8 °C under a coolant flow rate of 4 L/min and a coolant temperature of 65 °C. The observed thermal performance of the ISG motor and inverter using the proposed cooling structures was found to be sufficient for heat loads under various real driving conditions for a hybrid electric vehicle (HEV.

  1. Generation of powerful terahertz emission in a beam-driven strong plasma turbulence

    CERN Document Server

    Arzhannikov, A V

    2012-01-01

    Generation of terahertz electromagnetic radiation due to coalescence of upper-hybrid waves in the long-wavelength region of strong plasma turbulence driven by a high-current relativistic electron beam in a magnetized plasma is investigated. The width of frequency spectrum as well as angular characteristics of this radiation for various values of plasma density and turbulence energy are calculated using the simple theoretical model adequately describing beam-plasma experiments at mirror traps. It is shown that the power density of electromagnetic emission at the second harmonic of plasma frequency in the terahertz range for these laboratory experiments can reach the level of 1 ${MW/cm}^3$ with 1% conversion efficiency of beam energy losses to electromagnetic emission.

  2. Exogenous nitric oxide (NO) generated by NO-plasma treatment modulates osteoprogenitor cells early differentiation

    Science.gov (United States)

    Elsaadany, Mostafa; Subramanian, Gayathri; Ayan, Halim; Yildirim-Ayan, Eda

    2015-09-01

    In this study, we investigated whether nitric oxide (NO) generated using a non-thermal plasma system can mediate osteoblastic differentiation of osteoprogenitor cells without creating toxicity. Our objective was to create an NO delivery mechanism using NO-dielectric barrier discharge (DBD) plasma that can generate and transport NO with controlled concentration to the area of interest to regulate osteoprogenitor cell activity. We built a non-thermal atmospheric pressure DBD plasma nozzle system based on our previously published design and similar designs in the literature. The electrical and spectral analyses demonstrated that N2 dissociated into NO under typical DBD voltage-current characteristics. We treated osteoprogenitor cells (MC3T3-E1) using NO-plasma treatment system. Our results demonstrated that we could control NO concentration within cell culture media and could introduce NO into the intracellular space using NO-plasma treatment with various treatment times. We confirmed that NO-plasma treatment maintained cell viability and did not create any toxicity even with prolonged treatment durations. Finally, we demonstrated that NO-plasma treatment induced early osteogenic differentiation in the absence of pro-osteogenic growth factors/proteins. These findings suggest that through the NO-plasma treatment system we are able to generate and transport tissue-specific amounts of NO to an area of interest to mediate osteoprogenitor cell activity without subsequent toxicity. This opens up the possibility to develop DBD plasma-assisted tissue-specific NO delivery strategies for therapeutic intervention in the prevention and treatment of bone diseases.

  3. Generation of high-field narrowband terahertz radiation by counterpropagating plasma wakes

    CERN Document Server

    Timofeev, I V; Volchok, E P

    2016-01-01

    It is found that nonlinear interaction of plasma wakefields driven by counterpropagating laser or particle beams can efficiently generate high-power electromagnetic radiation at the second harmonic of the plasma frequency. Using a simple analytical theory and particle-in-cell simulations, we show that this phenomenon can be attractive for producing high-field ($\\sim 10$ MV/cm) narrowband terahertz pulses with the gigawatt power level and millijoule energy content.

  4. Divertor conditions relevant for fusion reactors achieved with linear plasma generator

    NARCIS (Netherlands)

    van Eck, H. J. N.; Kleyn, A. W.; Lof, A.; van der Meiden, H. J.; van Rooij, G. J.; Scholten, J.; van Emmichoven, P. A. Zeijlma

    2012-01-01

    Intense magnetized hydrogen and deuterium plasmas have been produced with electron densities up to 3.6 × 1020 m−3 and electron temperatures up to 3.7 eV with a linear plasma generator. Exposure of a W target has led to average heat and particle flux densities well in excess of 4 MW m−2 and 1024 m−2

  5. Divertor conditions relevant for fusion reactors achieved with linear plasma generator

    NARCIS (Netherlands)

    H.J.N. van Eck; A.W. Kleijn; A. Lof; H.J. van der Meiden; G.J. van Rooij; J. Scholten; P.A. Zeijlmans van Emmichoven

    2012-01-01

    Intense magnetized hydrogen and deuterium plasmas have been produced with electron densities up to 3.6 × 10 20 m−3 and electron temperatures up to 3.7 eV with a linear plasma generator. Exposure of a W target has led to average heat and particle flux densities well in excess of 4 MW m−2 and 10 24 m−

  6. Generation of a neutral, high-density electron-positron plasma in the laboratory

    CERN Document Server

    Sarri, G; Cole, J; Schumaker, W; Di Piazza, A; Reville, B; Doria, D; Dromey, B; Gizzi, L; Green, A; Grittani, G; Kar, S; Keitel, C H; Krushelnick, K; Kushel, S; Mangles, S; Najmudin, Z; Thomas, A G R; Vargas, M; Zepf, M

    2013-01-01

    We report on the laser-driven generation of purely neutral, relativistic electron-positron pair plasmas. The overall charge neutrality, high average Lorentz factor ($\\gamma_{e/p} \\approx 15$), small divergence ($\\theta_{e/p} \\approx 10 - 20$ mrad), and high density ($n_{e/p}\\simeq 10^{15}$cm$^{-3}$) of these plasmas open the pathway for the experimental study of the dynamics of this exotic state of matter, in regimes that are of relevance to electron-positron astrophysical plasmas.

  7. Low Temperature Plasmas Generated and Sustained Indefinitely Using a Focused Microwave Beam

    Science.gov (United States)

    Reid, Remington; Hoff, Brad; Lepell, Paul; AFRL Team

    2016-10-01

    The Air Force Research Laboratory has constructed a device that can initiate a plasma discharge in a focused microwave beam and sustain it indefinitely. A 10 kW, 4.5 GHz beam is passed through a vacuum chamber outfitted with pressure windows that are transparent to 4.5 GHz radiation. The pressure windows are large enough in diameter to prevent any interactions between the beam and the metallic chamber. The entire experiment is housed inside an anechoic chamber to minimize reflections. This novel plasma source generates low temperature, low density plasmas that have no contact with the walls which minimizes contamination and sheath formation.

  8. Characteristics of Plasma Shock Waves Generated in the Pulsed Laser Ablation Process

    Institute of Scientific and Technical Information of China (English)

    李智华; 张端明; 郁伯铭; 关丽

    2002-01-01

    We modify the Sedov theory to describe plasma shock waves generated in a pulsed laser ablating process. We also study the propagation characteristics of plasma shock waves during the preparation process of functional thin films deposited by a pulsed laser. In particular, we discuss in detail the temporal behaviour of energy causing the difference of the propagation characteristics between the plasma shock wave and the ideal shock wave in the point explosion model. Under the same experimental conditions, the theoretical results calculated with our modified Sedov theory are in good agreement with the existing experimental data.

  9. Numerical simulation of discharge plasma generation and nitriding the metals and alloys

    Science.gov (United States)

    Koval, T. V.; Manakov, R. A.; Nguyen Bao, Hung; Tran My, Kim An

    2017-01-01

    This research provides the numerical simulation of the plasma generation in a hollow cathode as well as the diffusion of nitrogen atoms into the metal in the low-pressure glow discharge plasma. The characteristics of the gas discharge were obtained and the relation of the basic technological parameters and the structural and phase state of the nitrided material were defined. Authors provided the comparison of calculations with the experimental results of titanium nitriding by low-pressure glow discharge plasma in a hollow cathode.

  10. Charged particle flows in an explosively generated non-ideal plasma

    Science.gov (United States)

    Boswell, C. J.; Carney, J. R.; Wilkinson, J.; Pangilinan, G. I.; Whitley, V. H.

    2007-06-01

    Non-ideal plasmas occur as a result of the stimulation of matter by strong shocks, detonation waves, or concentrated laser irradiation. Since all of these methods of generating non-ideal plasmas are already in use to address other problems, we focus on a detailed understanding of this plasma. In particular, we study the flow of charged particles in a non-ideal plasma generated using an explosive to compress the gas into the non- ideal plasma state. The shock wave in the gas is generated by an explosive located at one end of a guide tube filled with the gas. The detonation produces a shock wave strong enough to ionize the gas. Spectral line emission profiles, recorded with a streak emission spectroscopy system, are used to ascertain neutral and ionized gas properties. The electric and magnetic fields are measured by electrostatic probes and magnetic induction coils which permit the measurement of the temperature, density, and electric potential of the non-ideal plasma; as well as the flow of net electric charges respectively. The results demonstrate that a separation of the positive and negative charges occurs in the vicinity of the shock wave.

  11. Impact of cercal air currents on singing motor pattern generation in the cricket (Gryllus bimaculatus DeGeer)

    Science.gov (United States)

    2015-01-01

    The cercal system of crickets detects low-frequency air currents produced by approaching predators and self-generated air currents during singing, which may provide sensory feedback to the singing motor network. We analyzed the effect of cercal stimulation on singing motor pattern generation to reveal the response of a singing interneuron to predator-like signals and to elucidate the possible role of self-generated air currents during singing. In fictive singing males, we recorded an interneuron of the singing network while applying air currents to the cerci; additionally, we analyzed the effect of abolishing the cercal system in freely singing males. In fictively singing crickets, the effect of short air stimuli is either to terminate prematurely or to lengthen the interchirp interval, depending on their phase in the chirp cycle. Within our stimulation paradigm, air stimuli of different velocities and durations always elicited an inhibitory postsynaptic potential in the singing interneuron. Current injection in the singing interneuron elicited singing motor activity, even during the air current-evoked inhibitory input from the cercal pathway. The disruptive effects of air stimuli on the fictive singing pattern and the inhibitory response of the singing interneuron point toward the cercal system being involved in initiating avoidance responses in singing crickets, according to the established role of cerci in a predator escape pathway. After abolishing the activity of the cercal system, the timing of natural singing activity was not significantly altered. Our study provides no evidence that self-generated cercal sensory activity has a feedback function for singing motor pattern generation. PMID:26334014

  12. A study of increasing radical density and etch rate using remote plasma generator system

    Science.gov (United States)

    Lee, Jaewon; Kim, Kyunghyun; Cho, Sung-Won; Chung, Chin-Wook

    2013-09-01

    To improve radical density without changing electron temperature, remote plasma generator (RPG) is applied. Multistep dissociation of the polyatomic molecule was performed using RPG system. RPG is installed to inductively coupled type processing reactor; electrons, positive ions, radicals and polyatomic molecule generated in RPG and they diffused to processing reactor. The processing reactor dissociates the polyatomic molecules with inductively coupled power. The polyatomic molecules are dissociated by the processing reactor that is operated by inductively coupled power. Therefore, the multistep dissociation system generates more radicals than single-step system. The RPG was composed with two cylinder type inductively coupled plasma (ICP) using 400 kHz RF power and nitrogen gas. The processing reactor composed with two turn antenna with 13.56 MHz RF power. Plasma density, electron temperature and radical density were measured with electrical probe and optical methods.

  13. Analisis Motor Induksi Fasa Tiga Tipe Rotor Sangkar Sebagai Generator Induksi Dengan Variasi Hubungan Kapasitor Untuk Eksitasi

    Directory of Open Access Journals (Sweden)

    Rahmi Berlianti

    2015-03-01

    Full Text Available Three-phase induction motor can be operated as a three-phase induction generator.The tendency to use induction generators (rotor cage as subtitute of a synchronous generator is also increasing, especially for small MHP with lighting load (resistive. Its because of the dificulty, hard to find in the market, and high cost,induction generator self-excitation has many advantages than synchronous generator. However, the induction generator offers low voltage regulation and its value depends on the driving speed, capacitors, and the load. In this study, a three-phase induction motor ( rotor cage 0.9 KW, 2.7 A, pf 0.84, 50 Hz used as an induction generator, with capasitor connection variety, which capasitance value for star 25μF , Delta 8μF, C-2C 8μF and 16μF to load R-RL varied. And star connection capasitor with 25μF capasitance is better than others.

  14. Numerical simulation study of disk MHD generator for nonequilibrium plasma (NPG) system

    Energy Technology Data Exchange (ETDEWEB)

    Tsunoda, Kazumi [Shibaura Institute of Technology, Tokyo (Japan); Harada, Nob [Nagaoka Univ. of Technology (Japan)

    1995-12-31

    Design and performance prediction of a disk-shaped magnetohydrodynamic (MHD) generator, which is applied to the nonequilibrium plasma generator (NPG) system, have been carried out by means of a quasi-one-dimensional numerical simulation. The calculations have been performed for generator with constant height which is planned to be used for NPG-MHD disk generator pulse power demonstration. A maximum enthalpy extraction ratio obtained from the present calculation reached up to 20%, and, in this case, the electron temperature of working plasma fluctuated in the unstable regime against ionization instability. Taking into account this phenomenon, in order to obtain much higher generator performance, the MHD channel, in which electron temperature was kept at 5000 K, was designed. With this channel, enthalpy extraction ratio of 40% and output power of 7.2 MW were achieved without major modification of the supersonic nozzle, the inlet swirl vanes and the configuration of magnet system.

  15. Motor/generator and electronic control considerations for energy storage flywheels

    Science.gov (United States)

    Nola, F. J.

    1984-01-01

    A spacecraft electric power supply system is described. Requirements of the system are to accelerate a momentum wheel to a fixed maximum speed when solar energy is available and to maintain a constant voltage on the spacecraft bus under varying loads when solar energy is not available. Candidate motor types, pulse width modulated current control systems, and efficiency considerations are discussed. In addition, the Lunar Roving Vehicle motors are described along with their respective efficiencies.

  16. Analysis and characterization of microwave plasma generated with rectangular all-dielectric resonators

    Science.gov (United States)

    Kourtzanidis, K.; Raja, L. L.

    2017-04-01

    We report on a computational modeling study of small scale plasma discharge formation with rectangular dielectric resonators (DR). An array of rectangular dielectric slabs, separated by a gap of millimeter dimensions is used to provide resonant response when illuminated by an incident wave of 1.26 GHz. A coupled electromagnetic (EM) wave–plasma model is used to describe the breakdown, early response and steady state of the argon discharge. We characterize the plasma generation with respect to the input power, background gas pressure and gap size. It is found that the plasma discharge is generated mainly inside the gaps between the DR at positions that correspond to the antinodes of the resonant enhanced electric field pattern. The enhancement of the electric field inside the gaps is due to a combination of leaking and displacement current radiation from the DR. The plasma is sustained in over-critical densities due to the large skin depth with respect to the gap and plasma size. Electron densities are calculated in the order of {10}18{--}{10}19 {{{m}}}-3 for a gas pressure of 10 Torr, while they exceed 1020 {{{m}}}-3 in atmospheric conditions. Increase of input power leads to more intense ionization and thus faster plasma formation and results to a more symmetric plasma pattern. For low background gas pressure the discharge is diffusive and extends away from the gap region while in high pressure it is constricted inside the gap. An optimal gap size can be found to provide maximum EM energy transfer to the plasma. This fact demonstrates that the gap size dictates to a certain extent the resonant frequency and the Q-factor of the dielectric array and the breakdown fields can not be determined in a straight-forward way but they are functions of the resonators geometry and incident field frequency.

  17. Plasma-water systems studied with optical diagnostics including sum-frequency generation spectroscopy

    Science.gov (United States)

    Ito, Tsuyohito

    2016-09-01

    Recently, various applications of plasma-water systems have been reported, such as materials synthesis, agricultural applications, and medical treatments. As one of basic studies of such systems, we are investigating water surface structure influenced by a plasma via vibrational sum-frequency generation spectroscopy. Vibrational sum-frequency generation spectroscopy is known to be an interfacially active diagnostic technique, as such process occurs in noncentrosymmetric medium. Visible and wavenumber-tunable infrared beams are simultaneously irradiated to the interface. The interfacial water has ice-like ( 3200 cm-1), liquid-like ( 3400 cm-1), and free OH (3700 cm-1) structures (assignment of the ice-like structure still remains contentious), and the intensity of the signal becomes stronger when the tunable infrared beam resonates with a vibration of the structures. The results indicate that with generating air dielectric barrier discharges for supplying reactive species to the water surface, all investigated signals originating from the above-mentioned three structures decrease. Furthermore, the signal strengths are recovered after terminating the plasma generation. We currently believe that the surface density of the reactive species should be high when they are found at the water surface. Details on the experimental results of the sum-frequency generation spectroscopy, as well as other spectroscopic results of plasma-water systems, will be presented at the conference.

  18. Radiation-Hydrodynamic Simulation of Experiments With Intense Lasers Generating Collisionless Interpenetrating Plasmas

    Science.gov (United States)

    Grosskopf, Michael; Drake, R.; Kuranz, C.; Park, H.; Kugland, N.; Pollaine, S.; Ross, J.; Remington, B.; Spitkovsky, A.; Gargate, L.; Gregori, G.; Bell, A.; Murphy, C.; Meinecke, J.; Reville, B.; Sakawa, Y.; Kuramitsu, Y.; Takabe, H.; Froula, D.; Fiksel, G.; Miniati, F.; Koenig, M.; Ravasio, A.; Liang, E.; Woolsey, N.

    2012-05-01

    Collisionless shocks, shocks generated by plasma wave interactions in regions where the collisional mean-free-path for ions is long compared to the length scale for instabilities that generate magnetic fields, are found in many astrophysical systems such as supernova remnants and planetary bow shocks. Generating conditions to investigate collisionless shock physics is difficult to achieve in a laboratory setting; however, high-energy-density physics facilities have made this a possibility. Experiments whose goal is to investigate the production and growth of magnetic fields in collisionless shocks in laboratory-scale systems are being carried out on intense lasers, several of which are measuring the plasma properties and magnetic field strength in counter-streaming, collisionless flows generated by laser ablation. This poster reports radiation-hydrodynamic simulations using the CRASH code to model the ablative flow of plasma generated in order to assess potential designs, as well as infer properties of collected data from previous experiments. This work is funded by the Predictive Sciences Academic Alliances Program in NNSA-ASC via grant DEFC52- 08NA28616, by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-FG52-09NA29548, and by the National Laser User Facility Program, grant number DE-NA0000850.

  19. Study on Matching a 300 MVA Motor Generator with an Ohmic Heating Power Supply in HL-2M

    Science.gov (United States)

    Peng, Jianfei; Xuan, Weimin; Wang, Haibing; Li, Huajun; Wang, Yingqiao; Wang, Shujin

    2013-03-01

    A new 300 MVA/1350 MJ motor generator (MG) will be built to feed all of the poloidal field power supplies (PFPS) and auxiliary heating power supplies of the HL-2M tokamak. The MG has a vertical-shaft salient pole 6-phase synchronous generator and a coaxial 8500 kW induction motor. The Ohmic heating power supply (OHPS) consisting of 4-quadrant DC pulsed convertor is the one with the highest parameters among the PFPS. Therefore, the match between the generator and the OHPS is very important. The matching study with Matlab/Simulink is described in this paper. The simulation results show that the subtransient reactance of the generator is closely related to the inversion operation of the OHPS. By setting various subtransient reactance in the simulation generator model and considering the cost reduction, the optimized parameters are obtained as x″d = 0.405 p.u. at 100 Hz for the generator. The models built in the simulation can be used as an important tool for studying the dynamic characteristics and the control strategy of other HL-2M PFPSes.

  20. Determination of self generated magnetic field and the plasma density using Cotton Mouton polarimetry with two color probes

    Directory of Open Access Journals (Sweden)

    Joshi A.S.

    2013-11-01

    Full Text Available Self generated magnetic fields (SGMF in laser produced plasmas are conventionally determined by measuring the Faraday rotation angle of a linearly polarized laser probe beam passing through the plasma along with the interferogram for obtaining plasma density. In this paper, we propose a new method to obtain the plasma density and the SGMF distribution from two simultaneous measurements of Cotton Mouton polarimetry of two linearly polarized probe beams of different colors that pass through plasma in a direction normal to the planar target. It is shown that this technique allows us to determine the distribution of SGMF and the plasma density without doing interferometry of laser produced plasmas.

  1. Repetition priming of motor activity mediated by a central pattern generator: the importance of extrinsic vs. intrinsic program initiators.

    Science.gov (United States)

    Siniscalchi, Michael J; Cropper, Elizabeth C; Jing, Jian; Weiss, Klaudiusz R

    2016-10-01

    Repetition priming is characterized by increased performance as a behavior is repeated. Although this phenomenon is ubiquitous, mediating mechanisms are poorly understood. We address this issue in a model system, the feeding network of Aplysia This network generates both ingestive and egestive motor programs. Previous data suggest a chemical coding model: ingestive and egestive inputs to the feeding central pattern generator (CPG) release different modulators, which act via different second messengers to prime motor activity in different ways. The ingestive input to the CPG (neuron CBI-2) releases the peptides feeding circuit activating peptide and cerebral peptide 2, which produce an ingestive pattern of activity. The egestive input to the CPG (the esophageal nerve) releases the peptide small cardioactive peptide. This model is based on research that focused on a single aspect of motor control (radula opening). Here we ask whether repetition priming is observed if activity is triggered with a neuron within the core CPG itself and demonstrate that it is not. Moreover, previous studies demonstrated that effects of modulatory neurotransmitters that induce repetition priming persist. This suggests that it should be possible to "prime" motor programs triggered from within the CPG by first stimulating extrinsic modulatory inputs. We demonstrate that programs triggered after ingestive input activation are ingestive and programs triggered after egestive input activation are egestive. We ask where this priming occurs and demonstrate modifications within the CPG itself. This arrangement is likely to have important consequences for "task" switching, i.e., the cessation of one type of motor activity and the initiation of another. Copyright © 2016 the American Physiological Society.

  2. A Multiple Z-Pinch Configuration for the Generation of High-Density, Magnetized Plasmas

    Science.gov (United States)

    Tarditi, Alfonso G.

    2015-11-01

    The z-pinch is arguably the most straightforward and economical approach for the generation and confinement of hot plasmas, with a long history of theoretical investigations and experimental developments. While most of the past studies were focused on countering the natural tendency of z-pinches to develop instabilities, this study attempts to take advantage of those unstable regimes to form a quasi-stable plasma, with higher density and temperature, possibly of interest for a fusion reactor concept. For this purpose, a configuration with four z-pinch discharges, with axis parallel to each other and symmetrically positioned, is considered. Electrodes for the generation of the discharges and magnetic coils are arranged to favor the formation of concave discharge patterns. The mutual attraction from the co-streaming discharge currents enhances this pattern, leading to bent plasma streams, all nearing towards the axis. This configuration is intended to excite and sustain a ``kink'' unstable mode for each z-pinch, eventually producing either plasmoid structures, detached from each discharge, or sustained kink patterns: both these cases appear to lead to plasmas merging in the central region. The feasibility of this approach in creating a higher density, hotter, meta-stable plasma regime is investigated computationally, addressing both the kink excitation phase and the dynamics of the converging plasma columns.

  3. Ar plasma treated polytetrafluoroethylene films for a highly efficient triboelectric generator

    Science.gov (United States)

    Kim, Dong Yeong; Kim, Hyun Soo; Jung, Jong Hoon

    2016-12-01

    We report an Ar plasma treated polytetrafluoroethylene (PTFE) film based triboelectric device for a highly enhanced electric power generation. The plasma treatment of the PTFE in flowing Ar gas results in a sharp increase in surface roughness ( 46 nm), as compared with the as-received film ( 25 nm). In addition, the F ion content decreases whereas the O ion increases with increasing plasma reaction time. Because of the increased number of polar O ions, the surface becomes hydrophilic, as confirmed by water contact angle measurements. After the Ar plasma treatment, the PTFE based triboelectric device, which is periodically contacted with and separated from the ITO electrode, generates a 715 V open-circuit voltage and a 16 μA closed-circuit current, which are almost 79 and 32 times larger than those for as-received PTFE based device. Using the Ar plasma treated PTFE based triboelectric generator, we can turn on the 120 light emitting diodes (LEDs) without any batteries.

  4. Generation and detection of whistler wave induced space plasma turbulence at Gakona, Alaska

    Science.gov (United States)

    Rooker, L. A.; Lee, M. C.; Pradipta, R.; Watkins, B. J.

    2013-07-01

    We report on high-frequency wave injection experiments using the beat wave technique to study the generation of very-low-frequency (VLF) whistler waves in the ionosphere above Gakona, Alaska. This work is aimed at investigating whistler wave interactions with ionospheric plasmas and radiation belts. The beat wave technique involves injecting two X-mode waves at a difference frequency in the VLF range using the High-frequency Active Auroral Research Program (HAARP) heating facility. A sequence of beat wave-generated whistler waves at 2, 6.5, 7.5, 8.5, 9.5, 11.5, 15.5, 22.5, 28.5 and 40.5 kHz were detected in our 2011 experiments. We present Modular Ultra-high-frequency Ionospheric Radar (MUIR) (446 MHz) measurements of ion lines as the primary diagnosis of ionospheric plasma effects caused by beat wave-generated whistler waves. A magnetometer and digisonde were used to monitor the background ionospheric plasma conditions throughout the experiments. Our theoretical and data analyses show that VLF whistler waves can effectively interact with ionospheric plasmas via two different four-wave interaction processes leading to energization of electrons and ions. These preliminary results support our Arecibo experiments to study NAU-launched 40.75 kHz whistler wave interactions with space plasmas.

  5. High-Power Tunable Laser Pulse Driven Terahertz Generation in Corrugated Plasma Waveguides

    Science.gov (United States)

    Miao, Chenlong; Palastro, John; Antonsen, Thomas

    2016-10-01

    Excitation of terahertz radiation by the interaction of an ultra-short laser pulse and the fields of a miniature, corrugated plasma waveguide is considered. Plasma structures of this type have been realized experimentally and they can support electromagnetic (EM) channel modes with properties that allow for radiation generation. In particular, the mode have subluminal field components, thus allowing phase matching between the generated THz modes and the ponderomotive potential of the laser pulse. Theoretical analysis and full format PIC simulations are conducted. We find THz generated by this slow wave phase matching mechanism is characterized by lateral emission and a coherent, narrow band, tunable spectrum with relatively high power and conversion efficiency. We investigated two different types of channels, and a range of realistic laser pulses and plasma profile parameters are considered with the goal of increasing the conversion of optical energy to THz radiation. We find high laser intensities strongly modify the THz spectrum by exciting higher order channel modes. Enhancement of a specific channel mode can be realized by using an optimum pulse duration and plasma density. As an example, a fixed drive pulse (0.55 J) with spot size of 15 µm and pulse duration of 15 fs excites 37.8 mJ of THz radiation in a 1.5 cm corrugated plasma waveguide with on axis average density of 1.4×1018cm-3, conversion efficiency exceeding 8% is achieved.

  6. Manipulation of laser-generated energetic proton spectra in near critical density plasma

    Science.gov (United States)

    Palmer, Charlotte A. J.; Dover, Nicholas P.; Pogorelsky, Igor; Streeter, Matthew J. V.; Najmudin, Zulfikar

    2015-01-01

    We present simulations that demonstrate the production of quasi-monoenergetic proton bunches from the interaction of a CO2 laser pulse train with a near-critical density hydrogen plasma. The multi-pulse structure of the laser leads to a steepening of the plasma density gradient, which the simulations show is necessary for the formation of narrow-energy spread proton bunches. Laser interactions with a long, front surface, scale-length (>> c/ωp ) plasma, with linear density gradient, were observed to generate proton beams with a higher maximum energy, but a much broader spectrum compared to step-like density profiles. In the step-like cases, a peak in the proton energy spectra was formed and seen to scale linearly with the ratio of laser intensity to plasma density.

  7. High quality electron beam generation in a proton-driven hollow plasma wakefield accelerator

    CERN Document Server

    Li, Yangmei; Lotov, Konstantin V; Sosedkin, Alexander P; Hanahoe, Kieran; Mete-Apsimon, Oznur

    2016-01-01

    Proton-driven plasma wakefield accelerators have numerically demonstrated substantially higher accelerating gradients compared to conventional accelerators and the viability of accelerating electrons to energy frontier in a single plasma stage. However, due to the intrinsic strong and radially varying transverse fields, the beam quality is still far from suitable for practical application in future colliders. Here we propose a new accelerating region which is free from both plasma electrons and ions in the proton-driven hollow plasma channel. The high quality electron beam is therefore generated with this scheme without transverse plasma fields. The results show that a 1 TeV proton driver can propagate and accelerate an electron beam to 0.62 TeV with correlated energy spread of 4.6% and well-preserved normalized emittance below 2.4 mm mrad in a single hollow plasma channel of 700 m. More importantly, the beam loading tolerance is significantly improved compared to the uniform plasma case. This high quality an...

  8. Computational design of faster rotating second-generation light-driven molecular motors by control of steric effects.

    Science.gov (United States)

    Oruganti, Baswanth; Fang, Changfeng; Durbeej, Bo

    2015-09-07

    We report a systematic computational investigation of the possibility to accelerate the rate-limiting thermal isomerizations of the rotary cycles of synthetic light-driven overcrowded alkene-based molecular motors through modulation of steric interactions. Choosing as a reference system a second-generation motor known to accomplish rotary motion in the MHz regime and using density functional theory methods, we propose a three-step mechanism for the thermal isomerizations of this motor and show that variation of the steric bulkiness of the substituent at the stereocenter can reduce the (already small) free-energy barrier of the rate-determining step by a further 15-17 kJ mol(-1). This finding holds promise for future motors of this kind to reach beyond the MHz regime. Furthermore, we demonstrate and explain why one particular step is kinetically favored by decreasing and another step is kinetically favored by increasing the steric bulkiness of this substituent, and identify a possible back reaction capable of impeding the rotary rate.

  9. About the Power Generation Confirmation of the Induction Motor and the Influence on the Islanding Detection Device

    Science.gov (United States)

    Igarashi, Hironobu; Sato, Takashi; Miyamoto, Kazunori; Kurokawa, Kousuke

    The photovoltaic generation system must have protection device and islanding detection devices to connect with utility line of the electric power company. It is regulated in the technological requirement guideline and the electric equipment technology standard that the country provides. The islanding detection device detected purpose install for blackout due to the accident occurrence of the earth fault and the short-circuit in the utility line. When the islanding detection device detects the power blackout, it is necessary to stop the photovoltaic generation system immediately. If the photovoltaic generation system is not stopped immediately, electricity comes to charge the utility power line very at risk. We had already known that the islanding detection device can't detect the islanding phenomenon, if is there the induction motor in the loads. Authors decided to investigate the influence that the induction motors gave to the islanding detection device. The result was the load condition that the induction motors changed generator the voltage is restraining. Moreover, it was clarified that the time of the islanding was long compared with the load condition of not changing into the state of the generator. The value changes into the reactance of the induction motors according to the frequency change after the supply of electric power line stops. The frequency after the supply of electric power line stops changes for the unbalance the reactive power by the effect of the power rate constancy control with PLL of the power conditioner. However, the induction motors is also to the changing frequency, makes amends for the amount of reactive power, and the change in the frequency after the supply of electric power line stops as a result is controlled. When the frequency changed after the supply of electric power line stopped, it was clarified of the action on the direction where it made amends from the change of the constant for the amount of an invalid electric power, and

  10. Plasma Processing of SRF Cavities for the next Generation Of Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Vuskovic, Leposava

    2015-11-23

    The cost-effective production of high frequency accelerating fields are the foundation for the next generation of particle accelerators. The Ar/Cl2 plasma etching technology holds the promise to yield a major reduction in cavity preparation costs. Plasma-based dry niobium surface treatment provides an excellent opportunity to remove bulk niobium, eliminate surface imperfections, increase cavity quality factor, and bring accelerating fields to higher levels. At the same time, the developed technology will be more environmentally friendly than the hydrogen fluoride-based wet etching technology. Plasma etching of inner surfaces of standard multi-cell SRF cavities is the main goal of this research in order to eliminate contaminants, including niobium oxides, in the penetration depth region. Successful plasma processing of multi-cell cavities will establish this method as a viable technique in the quest for more efficient components of next generation particle accelerators. In this project the single-cell pill box cavity plasma etching system is developed and etching conditions are determined. An actual single cell SRF cavity (1497 MHz) is plasma etched based on the pill box cavity results. The first RF test of this plasma etched cavity at cryogenic temperature is obtained. The system can also be used for other surface modifications, including tailoring niobium surface properties, surface passivation or nitriding for better performance of SRF cavities. The results of this plasma processing technology may be applied to most of the current SRF cavity fabrication projects. In the course of this project it has been demonstrated that a capacitively coupled radio-frequency discharge can be successfully used for etching curved niobium surfaces, in particular the inner walls of SRF cavities. The results could also be applicable to the inner or concave surfaces of any 3D structure other than an SRF cavity.

  11. BN coatings deposition by magnetron sputtering of B and BN targets in electron beam generated plasma

    Science.gov (United States)

    Kamenetskikh, A. S.; Gavrilov, N. V.; Koryakova, O. V.; Cholakh, S. O.

    2017-05-01

    Boron nitride coatings were deposited by reactive pulsed magnetron sputtering of B and BN targets (50 kHz, 10 µs for B; 13.56 MHz for BN) at 2-20 mA/cm2 ion current density on the substrate. The effect of electron beam generated plasma on characteristics of magnetron discharge and phase composition of coatings was studied.

  12. A high efficiency motor/generator for magnetically suspended flywheel energy storage system

    Science.gov (United States)

    Niemeyer, W. L.; Studer, P.; Kirk, J. A.; Anand, D. K.; Zmood, R. B.

    1989-01-01

    The authors discuss the theory and design of a brushless direct current motor for use in a flywheel energy storage system. The motor design is optimized for a nominal 4.5-in outside diameter operating within a speed range of 33,000-66,000 revolutions per minute with a 140-V maximum supply voltage. The equations which govern the motor's operation are used to compute a series of acceptable design parameter combinations for ideal operation. Engineering tradeoffs are then performed to minimize the irrecoverable energy loss while remaining within the design constraint boundaries. A final integrated structural design whose features allow it to be incorporated with the 500-Wh magnetically suspended flywheel is presented.

  13. The Importance of Lateral Connections in the Parietal Cortex for Generating Motor Plans.

    Directory of Open Access Journals (Sweden)

    Derrik E Asher

    Full Text Available Substantial evidence has highlighted the significant role of associative brain areas, such as the posterior parietal cortex (PPC in transforming multimodal sensory information into motor plans. However, little is known about how different sensory information, which can have different delays or be absent, combines to produce a motor plan, such as executing a reaching movement. To address these issues, we constructed four biologically plausible network architectures to simulate PPC: 1 feedforward from sensory input to the PPC to a motor output area, 2 feedforward with the addition of an efference copy from the motor area, 3 feedforward with the addition of lateral or recurrent connectivity across PPC neurons, and 4 feedforward plus efference copy, and lateral connections. Using an evolutionary strategy, the connectivity of these network architectures was evolved to execute visually guided movements, where the target stimulus provided visual input for the entirety of each trial. The models were then tested on a memory guided motor task, where the visual target disappeared after a short duration. Sensory input to the neural networks had sensory delays consistent with results from monkey studies. We found that lateral connections within the PPC resulted in smoother movements and were necessary for accurate movements in the absence of visual input. The addition of lateral connections resulted in velocity profiles consistent with those observed in human and non-human primate visually guided studies of reaching, and allowed for smooth, rapid, and accurate movements under all conditions. In contrast, Feedforward or Feedback architectures were insufficient to overcome these challenges. Our results suggest that intrinsic lateral connections are critical for executing accurate, smooth motor plans.

  14. Atmospheric plasma generates oxygen atoms as oxidizing species in aqueous solutions

    Science.gov (United States)

    Mokhtar Hefny, Mohamed; Pattyn, Cedric; Lukes, Petr; Benedikt, Jan

    2016-10-01

    A remote microscale atmospheric pressure plasma jet (µAPPJ) with He, He/H2O, He/O2, and He/O2/H2O gas mixtures was used to study the transport of reactive species from the gas phase into the liquid and the following aqueous phase chemistry. The effects induced by the µAPPJ in water were quantitatively studied using phenol as a chemical probe and by measuring H2O2 concentration and pH values. These results were combined with the analysis of the absolute densities of the reactive species and the modeling of convective/diffusion transport and recombination reactions in the effluent of the plasma jet. Additionally, modified plasma jets were used to show that the role of emitted photons in aqueous chemistry is negligible for these plasma sources. The fastest phenol degradation was measured for the He/O2 plasma, followed by He/H2O, He/O2/H2O, and He plasmas. The modeled quantitative flux of O atoms into the liquid in the He/O2 plasma case was highly comparable with the phenol degradation rate and showed a very high transfer efficiency of reactive species from the plasma into the liquid, where more than half of the O atoms leaving the jet nozzle entered the liquid. The results indicate that the high oxidative effect of He/O2 plasma was primarily due to solvated O atoms, whereas OH radicals dominated the oxidative effects induced in water by plasmas with other gas mixtures. These findings help to understand, in a quantitative way, the complex interaction of cold atmospheric plasmas with aqueous solutions and will allow a better understanding of the interaction of these plasmas with water or buffered solutions containing biological macromolecules, microorganisms, or even eukaryotic cells. Additionally, the µAPPJ He/O2 plasma source seems to be an ideal tool for the generation of O atoms in aqueous solutions for any future studies of their reactivity.

  15. Methods of Generation and Detailed Characterization of Millimeter-Scale Plasmas Using a Gasbag Target

    Institute of Scientific and Technical Information of China (English)

    李志超; 尹强; 朱芳华; 郭亮; 袁鹏; 刘慎业; 丁永坤; 郑坚; 蒋小华; 王哲斌; 杨冬; 章欢; 李三伟; 王峰; 彭晓世

    2011-01-01

    Gasbag targets are useful for the research of laser-plasma interactions in inertial confinement fusion,especial in the laser overlapping regime.We report that on the Shengguang-Ⅱ laser facility,millimeter-scale plasm are successfully generated by four 0.35 μm laser beams using a gasbag target.Multiple diagnostics are applied to characterize the millimeter-scale plasmas in detail.The images from the x-ray pinhole cameras confirm that millimeter-scale plasmas are indeed created.An optical Thomson scattering system diagnoses the electron temperature of the CH filling plasmas by probing the thermal ion-acoustic fluctuations,which indicates that the electron temperature has a 600eV fiat roof in 0.7-1.3ns.Another key parameter,i.e.the electron density of the millimeter-scale plasmas,is inferred by the spectrum of the back stimulated Raman scattering of an addition 0.53 μm laser beam.The inferred electron density keeps stable at 0.1nc in early time consistent with the controlled filling pressure and splits into a higher density in late time,which is attributed to the blast wave entering in the SRS interaction region.%Gasbag targets are useful for the research of laser-plasma interactions in inertial confinement fusion, especially in the laser overlapping regime. We report that on the Shengguang-S laser facility, millimeter-scale plasmas are successfully generated by four 0.35 \\im laser beams using a gasbag target. Multiple diagnostics are applied to characterize the millimeter-scale plasmas in detail. The images from the x-ray pinhole cameras confirm that millimeter-scale plasmas are indeed created. An optical Thomson scattering system diagnoses the electron temperature of the CH filling plasmas by probing the thermal ion-acoustic fluctuations, which indicates that the electron temperature has a 600eV flat roof in 0.7-1.3ns. Another key parameter, I.e. The electron density of the millimeter-scale plasmas, is inferred by the spectrum of the back stimulated Raman

  16. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

    Energy Technology Data Exchange (ETDEWEB)

    Jablonowski, H.; Hammer, M. U.; Reuter, S. [Center for Innovation Competence plasmatis, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Bussiahn, R.; Weltmann, K.-D.; Woedtke, Th. von [Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2015-12-15

    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100–400 nm) and, in particular, vacuum ultraviolet (VUV, 10–200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH{sub 2}O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H{sub 2}O{sub 2}) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O{sub 2}{sup •−}) and hydroxyl radicals ({sup •}OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  17. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

    Science.gov (United States)

    Jablonowski, H.; Bussiahn, R.; Hammer, M. U.; Weltmann, K.-D.; von Woedtke, Th.; Reuter, S.

    2015-12-01

    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100-400 nm) and, in particular, vacuum ultraviolet (VUV, 10-200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH2O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H2O2) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O2•-) and hydroxyl radicals (•OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  18. CERN LINAC4 H- Source and SPL plasma generator RF systems, RF power coupling and impedance measurements

    CERN Document Server

    Paoluzzi, M; Marques-Balula, J; Nisbet, D

    2010-01-01

    In the LINAC4 H- source and the SPL plasma generator at CERN, the plasma is heated by a 100 kW, 2 MHz RF system. Matching of the load impedance to the final amplifier is achieved with a resonant network. The system implements a servo loop for power stabilization and frequency hopping to cope with the detuning effects induced by the plasma. This paper provides a detailed description of the system, including the pulse rate increase to 50 Hz for use in the SPL plasma generator. The performances, measurements of RF power coupling, contribution of the plasma to the impedance as well as first operation are reported.

  19. Generation of fast highly charged ions in laser-plasma interaction

    Energy Technology Data Exchange (ETDEWEB)

    Wolowski, J [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Badziak, J [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Boody, F P [Ion Light Technologies GmbH, Bad Abbach (Germany); Czarnecka, A [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Gammino, S [INFN-Laboratori Nazionali del Sud, Catania (Italy); Jablonski, S [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Krasa, J [Institute of Physics, ASCR (Czech Republic); Laska, L [Institute of Physics, ASCR (Czech Republic); Parys, P [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Rohlena, K [Institute of Physics, ASCR (Czech Republic); Rosinski, M [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Ryc, L [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Torrisi, L [INFN-Laboratori Nazionali del Sud, Catania (Italy); Ullschmied, J [IPALS Research Centre ASCR, Prague (Czech Republic)

    2006-12-15

    The nonthermal and nonlinear coupling of strong laser light wave with plasma transfers a part of laser energy into hot electrons and fast ions. The efficiency of these effects depends on the characteristics of a laser pulse, target properties and irradiation geometry. The reported studies were performed with the use of a high-power and high-energy iodine PALS laser system (energy up to 1 kJ in a 0.4 ns pulse at wavelength of 1315 nm and energy up to 250 J at wavelength of 438 nm). The properties of the laser-produced ion streams were determined with the use of ion diagnostics based on the time-of-flight method. The characteristics of x-rays were measured using various semiconductor detectors. The main ion stream characteristics as well as the ion acceleration processes in plasmas of different Z numbers were studied in dependence on laser pulse parameters. The parameters of a fast ion group depend evidently on Z number of the ions. The influence of the electron density scale length on fast ion generation was investigated using a low intensity laser pre-pulses to generate preformed plasmas (pre-plasmas) with which the main laser pulse interacted. The obtained results suggest that ion acceleration processes were most effective at a specific electron density gradient scale length of pre-plasma determined by the pre-pulse parameters.

  20. Evaluation of Ash Toxicity Generated From the Thermal Plasma Pyrolysis of Used Automobile Tires

    Science.gov (United States)

    Chang, J. S.; Novog, D. R.; Jamal, S.

    1996-10-01

    The disposal of used tires represents a severe environmental problem. As the heat content of the rubber tires is even higher than that of coal it should be considered as a future source of alternate fuel for power generation. There have been attempts to burn old tires directly in cofired boilers for production of electricity. However, there are several environmental concerns since the combustion flue gas may contain a significant concentration heavy metals (Fe, Zn, Cd, As, etc.). One technique currently being developed is the pyrolyzation of rubber tires by a thermal plasma to produce combustible gases. In this work, ashes generated during the plasma pyrolysis of used automobile tires using a DC Argon thermal plasma were analyzed using Neutron Activation Analysis (NAA) and produced syngas composition was analyzed by FT-IR.. The gas analysis indicates a significant quantity of combustible gases (CH4, C2H2, C2H4, CO, H2 etc..) was produced from the thermal plasma pyrolysis of used tires. The results also indicate that a majority of the heavy metals present in used tires were concentrated in the ashes deposited in reaction chamber wall and in the two-stage filtering system. Furthermore the heavy metal concentration decreases significantly with increasing distance from the plasma torch. Toxic components such as Zn, As and Cl were also collected in the filtering process.

  1. Scavenging of hydroxyl radicals generated in human plasma following X-ray irradiation.

    Science.gov (United States)

    Hosokawa, Yoichiro; Sano, Tomoaki

    2015-11-01

    There are various antioxidant materials that scavenge free radicals in human plasma. It is possible that the radical-scavenging function causes a radiation protective effect in humans. This study estimated the hydroxyl (OH) radical-scavenging activity induced by X-ray irradiation in human plasma. The test subjects included 111 volunteers (75 males and 36 females) ranging from 22 to 35 years old (average, 24.0). OH radicals generated in irradiated human plasma were measured by electron spin resonance (ESR). The relationships between the amount of the OH radical and chemical and biological parameters [total protein, total cholesterol, triglycerides and hepatitis B surface (HBs) antibodies] were estimated in the plasma of the 111 volunteers by a multivariate analysis. The presence of HBs antibodies had the greatest influence on OH radical-scavenging activity. One volunteer who did not have the HBs antibody was given an inoculation of the hepatitis B vaccine. There was a remarkable decrease in the amount of OH radical generated from plasma after the HBs antibody was produced. The results indicate that the HBs antibody is an important factor for the scavenging of OH radicals initiated by X-ray irradiation in the human body.

  2. Study of an Atmospheric Pressure Plasma Jet of Argon Generated by Column Dielectric Barrier Discharge

    Science.gov (United States)

    Nur, M.; Kinandana, A. W.; Winarto, P.; Muhlisin, Z.; Nasrudin

    2016-11-01

    An atmospheric of argon plasma jet was generated by using column dielectric barrier discharge has been investigated. In this study, argon gas was passed through the capillary column by regulating the flow rate of gas. This atmospheric pressure plasma jet (APPJ) was generated by a sinusoidal AC high voltage in the range of 0.4 kV to 10 kV and at frequencies of 15 kHz and 26 kHz. APPJ has been produced with flow rate of argon gas from 1 litter/min - 10 litters/min. The electric current has been taken with variation of voltage and each interval argon gas flow rate of 1 litter/min. The results show that electric current increase linearly and then it trends to saturation condition by the increasing of applied voltage. We found also that the length of the plasma jet increase by augmenting of applied voltage both for frequencies of 15 kHz and 26 kHz. Furthermore, our results show that length of plasma jet optimum for flow rate of argon gas of 2 litters/minute. In addition, we obtained that the larger applied voltage, the greater the temperature of the plasma jet.

  3. Generation of intense circularly polarized attosecond light bursts from relativistic laser plasmas

    CERN Document Server

    Ma, Guangjin; Yu, M Y; Shen, Baifei; Veisz, Laszlo

    2016-01-01

    We have investigated the polarization of attosecond light bursts generated by nanobunches of electrons from relativistic few-cycle laser pulse interaction with the surface of overdense plasmas. Particle-in-cell simulation shows that the polarization state of the generated attosecond burst depends on the incident-pulse polarization, duration, carrier envelope phase, as well as the plasma scale length. Through laser and plasma parameter control, without compromise of generation efficiency, a linearly polarized laser pulse with azimuth $\\theta^i=10^\\circ$ can generate an elliptically polarized attosecond burst with azimuth $|\\theta^r_{\\rm atto}|\\approx61^\\circ$ and ellipticity $\\sigma^r_{\\rm atto}\\approx0.27$; while an elliptically polarized laser pulse with $\\sigma^i\\approx0.36$ can generate an almost circularly polarized attosecond burst with $\\sigma^r_{\\rm atto}\\approx0.95$. The results propose a new way to a table-top circularly polarized XUV source as a probe with attosecond scale time resolution for many a...

  4. Application of Super-Synchronization Speed Control Technology in Two 80 MVA Motor-Generator Units of HL-2A

    Institute of Scientific and Technical Information of China (English)

    LI Huajun; WANG Fen; WANG Xiaoping; DU Chang; XUAN Weiming; PEN Jianfei; HU Haotian; LIU Lin; KANG Li; XU Lirong; HUANG Zhaorong

    2007-01-01

    Two sets of super-synchronization speed control assemblies for two 80 MVA motorgenerator units have been developed successfully in order to satisfy the demand of the toroidal field system in the HL-2A tokamak.Based on the three-phase logical no-circumfluence a.c./a.c.cycloconverter,the speeds of two 2500 kW double fed drive motors have been regulated by means of the vector control technology.The maximum operating speed of each motor- generator unit has been raised from 1488 rpm (revolutions per minute) to 1650 rpm and the released energy of each unit during a pulsed discharge can reach 500 MJ.As a result,the toroidal field system has the capacity to provide 2.8 tesla (T) in HL-2A experiments.

  5. Development of plasma streamwise vortex generators for increased boundary layer control authority

    Science.gov (United States)

    Bowles, Patrick; Schatzman, David; Corke, Thomas; Thomas, Flint

    2009-11-01

    This experimental study focuses on active boundary layer flow control utilizing streamwise vorticity produced by a single dielectric barrier discharge plasma actuator. A novel plasma streamwise vortex generator (PSVG) layout is presented that mimics the passive flow control characteristics of the trapezoidal vane vortex generator. The PSVG consists of a common insulated electrode and multiple, exposed streamwise oriented electrodes used to produce counter-rotating vortical structures. Smoke and oil surface visualization of boundary layer flow over a flat plate compare the characteristics of passive control techniques and different PSVG designs. Passive and active control over a generic wall-mounted hump model, Rec = 288,000-575,000, are compared through static wall pressure measurements along the model's centerline. Different geometric effects of the PSVG electrode configuration were investigated. PSVG's with triangular exposed electrodes outperformed ordinary PSVG's under certain circumstances. The electrode arrangement produced flow control mechanisms and effectiveness similar to the passive trapezoidal vane vortex generators.

  6. In vitro generation of motor neuron precursors from mouse embryonic stem cells using mesoporous nanoparticles

    DEFF Research Database (Denmark)

    Garcia-Bennett, Alfonso E; König, Niclas; Abrahamsson, Ninnie

    2014-01-01

    Aim: Stem cell-derived motor neurons (MNs) are utilized to develop replacement strategies for spinal cord disorders. Differentiation of embryonic stem cells into MN precursors involves factors and their repeated administration. We investigated if delivery of factors loaded into mesoporous...

  7. Only Self-Generated Actions Create Sensori-Motor Systems in the Developing Brain

    Science.gov (United States)

    James, Karin Harman; Swain, Shelley N.

    2011-01-01

    Previous research shows that sensory and motor systems interact during perception, but how these connections among systems are created during development is unknown. The current work exposes young children to novel "verbs" and objects through either (a) actively exploring the objects or (b) by seeing an experimenter interact with the objects.…

  8. Plasma selenium is positively related to performance in neurological tasks assessing coordination and motor speed.

    Science.gov (United States)

    Shahar, Avner; Patel, Kushang V; Semba, Richard D; Bandinelli, Stefania; Shahar, Danit R; Ferrucci, Louigi; Guralnik, Jack M

    2010-09-15

    Parkinson's disease (PD) is a degenerative process affecting the striato nigral system (SN). Its etiology, although obscure, may involve oxidative damage. Selenium, an antioxidant, was shown to protect the SN in animal models. In the current study, we investigate the association between plasma selenium concentrations and the presence of "soft" neurological signs related to the SN. Plasma selenium concentration was assessed in participants of age ≥65 years in the InCHIANTI study, a population-based cohort study in Tuscany, Italy. PD was defined based on standard criteria. "Soft" neurological signs were ascertained by physical examination. A total of 1,012 participants were included. No association was found between the presence of PD and plasma selenium. There was, however, a strong association between plasma selenium and timed performance-based assessments. Lower levels of selenium were significantly associated withdecreased performance in neurological tests of coordination among older adults. Prospective studies are needed to further investigate the effects of selenium on SN dysfunction.

  9. Characteristics of a long and stable filamentary argon plasma jet generated in ambient atmosphere

    Science.gov (United States)

    Teodorescu, M.; Bazavan, M.; Ionita, E. R.; Dinescu, G.

    2015-04-01

    We present a study of a long (up to 60 mm) and thin (600 μm) plasma jet generated at 13.56 MHz in argon expanding in an open atmosphere from inside of a thin glass tube. The discharge is operated with one annular external electrode on the tube, in the absence of any grounded electrode in the discharge proximity. The study comprises image, spectral and electrical measurements, aiming to define and understand the operating domains of this plasma jet source. Two plasma zones were identified, which coexist: a long filament accompanied by a diffuse discharge. The coexistence of these plasma zones was studied in the power-mass flow rate parameter space. An electric model is proposed, considering the jet as a radiating antenna, which allows the determination of the main electrical parameters like capacitance, resistance and active RF power dissipated in the discharge. The specific zones on the I-V characteristics were assigned to the operating domains observed visually. The spectral emission of plasma has been used to characterize the jet in respect to the gas temperature, excitation temperature and plasma density.

  10. Influence of impact conditions on plasma generation during hypervelocity impact by aluminum projectile

    Science.gov (United States)

    Song, Weidong; Lv, Yangtao; Li, Jianqiao; Wang, Cheng; Ning, Jianguo

    2016-07-01

    For describing hypervelocity impact (relative low-speed as related to space debris and much lower than travelling speed of meteoroids) phenomenon associated with plasma generation, a self-developed 3D code was advanced to numerically simulate projectiles impacting on a rigid wall. The numerical results were combined with a new ionization model which was developed in an early study to calculate the ionized materials during the impact. The calculated results of ionization were compared with the empirical formulas concluded by experiments in references and a good agreement was obtained. Then based on the reliable 3D numerical code, a series of impacts with different projectile configurations were simulated to investigate the influence of impact conditions on hypervelocity impact generated plasma. It was found that the form of empirical formula needed to be modified. A new empirical formula with a critical impact velocity was advanced to describe the velocity dependence of plasma generation and the parameters of the modified formula were ensured by the comparison between the numerical predictions and the empirical formulas. For different projectile configurations, the changes of plasma charges with time are different but the integrals of charges on time almost stayed in the same level.

  11. Temperature and Nitric Oxide Generation in a Pulsed Arc Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    T.NAMIHIRA; S.SAKAI; M.MATSUDA; D.WANG; T.KIYAN; H.AKIYAMA; K.OKAMOTO; K.TODA

    2007-01-01

    Nitric oxide (NO) is increasingly being used in medical treatments of high blood pressure,acute respiratory distress syndrome and other illnesses related to the lungs.Currently a NO inhalation system consists of a gas cylinder of N2 mixed with a high concentration of NO.This arrangement is potentially risky due to the possibility of an accidental leak of NO from the cylinder.The presence of NO in the air leads to the formation of nitric dioxide (NO2),which is toxic to the lungs.Therefore,an on-site generator of NO would be highly desirable for medical doctors to use with patients with lung disease.To develop the NO inhalation system without a gas cylinder,which would include a high concentration of NO,NAMIHIRA et al have recently reported on the production of NO from room air using a pulsed arc discharge.In the present work,the temperature of the pulsed arc discharge plasma used to generate NO was measured to optimize the discharge condition.The results of the temperature measurements showed the temperature of the pulsed arc discharge plasma reached about 10,000 K immediately after discharge initiation and gradually decreased over tens of microseconds.In addition,it was found that NO was formed in a discharge plasma having temperatures higher than 9,000 K and a smaller input energy into the discharge plasma generates NO more efficiently than a larger one.

  12. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

    Directory of Open Access Journals (Sweden)

    C. Yong-Nong

    2013-03-01

    Full Text Available In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The powersupply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to theindispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer needconsidering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, butalso parasitic capacitance resulted from the insulation wrappings on the high-voltage side. This research exhibits asimple approach to measuring equivalent circuit parameters of the high-frequency, high-voltage transformer with straycapacitance being introduced into the conventional modeling. The proposed modeling scheme provides not only aprecise measurement procedure but also effective design information for series-load resonant converter. The plasmadischarging plate is designed as part of the electric circuit in the series load-resonant converter and the circuit modelof the plasma discharging plate is also conducted as well. Thus, the overall model of the high-voltage plasmagenerator is built and the designing procedures for appropriate selections of the corresponding resonant-circuitparameters can be established. Finally, a high-voltage plasma generator with 220V, 60Hz, and 1kW input, along witha 22 kHz and over 8kV output, is realized and implemented.

  13. Dynamics of surface plasma generation by the microsecond emission of the XeF laser

    Science.gov (United States)

    Min'ko, L. Ia.; Chumakov, A. N.; Efremov, V. V.; Bakeev, A. A.; Nikolashina, L. I.; Prokopenko, N. V.; Sorokin, V. A.

    1991-06-01

    The dynamics of surface plasma generation by the microsecond emission of the XeF laser and the interaction of the ultraviolet emission with absorbent materials and the plasma at atmospheric pressure were investigated experimentally. The XeF laser used in the experiments operated at a wavelength of 0.35 micron, with a maximum emergy of 30 J and a pulse width of 3 microsec; the target materials included aluminum, bismuth, and graphite. The experimental results are presented in graphic form and compared with theoretical data.

  14. Study of hot electrons generated from intense laser-plasma interaction employing Image Plate

    Institute of Scientific and Technical Information of China (English)

    LIANG WenXi; JIN Zhan; WEI ZhiYi; ZHAO Wei; LI YingJun; ZHANG Jie; LI YuTong; XU MiaoHua; YUAN XiaoHui; ZHENG ZhiYuan; ZHANG Yi; LIU Feng; WANG ZhaoHua; LI HanMing

    2008-01-01

    Image Plate (IP) is convenient to be used and very suitable for radiation detection because of its advantages such as wide dynamic range, high detective quantum efficiency, ultrahigh sensitivity and superior linearity. The function mechanism and characteristics of IP are introduced in this paper. IP was employed in the study of hot electrons generated from intense laser-plasma interaction. The angular distri-bution and energy spectrum of hot electrons were measured with IP in the experi-ments. The results demonstrate that IP is an effective radiation detector for the study of laser-plasma interaction.

  15. Study of hot electrons generated from intense laser-plasma interaction employing Image Plate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Image Plate (IP) is convenient to be used and very suitable for radiation detection because of its advantages such as wide dynamic range, high detective quantum efficiency, ultrahigh sensitivity and superior linearity. The function mechanism and characteristics of IP are introduced in this paper. IP was employed in the study of hot electrons generated from intense laser-plasma interaction. The angular distri- bution and energy spectrum of hot electrons were measured with IP in the experi- ments. The results demonstrate that IP is an effective radiation detector for the study of laser-plasma interaction.

  16. 应用于风力发电机的永磁双转子电机%Permanent Magnet Double Rotor Motor used in Wind Power Generator

    Institute of Scientific and Technical Information of China (English)

    孙屹东; 黄坚

    2015-01-01

    Permanent magnet double rotor motor is a kind of novel composite motor, composed of a stator and the inner, outer two rotors, the motor has the characteristics of asynchronous motor and synchronous motor. Based on the characteristics of double rotor permanent magnet motor, it was used in wind power generation system. Compared with the traditional wind power system, this motor is simple, easy maintenance and other advantages. And this motor can improve the power factor of power generation system, efficiency and reliability, and obviously reduce the investment cost of wind power generation system etc.%永磁双转子电机是由一个定子和内、外二个转子构成的新颖的复合电机,该电机具有异步电动机运行的特点,且兼顾同步电机的电气特性。基于永磁双转子电机这一特点,应用于风力发电机,与传统的风力发电系统相比,具有发电系统简单、维护方便等优势,同时可提高发电系统的功率因数、效率和可靠性,并可明显降低风力发电系统的投资费用等。

  17. Cost of electricity generated in motor-generator set using biogas of swine; Custo da eletricidade gerada em conjunto motor gerador utilizando biogas da suinocultura

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Samuel N. Melegari de; Pavan, Andre Aparecido [Faculdade Assis Gurgacz - FAG, Cascavel, PR (Brazil)], e-mail: ssouza@unioeste.br; Pereira, William Caldart [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil). Centro de Ciencias Exatas e Tecnologicas. Programa Institucional de Bolsas de Iniciacao Cientifica

    2004-07-01

    One of the largest available sources of energy in the rural areas and agroindustrial is the biomass. The same appears in the form of vegetable residues and you encourage, such as crop remains, animal manure, energy plantations and agroindustrial effluents. These residues can be used by the rural producer or agroindustry for it burns it direct, seeking the production of heat or biogas production in biodigestor. Close to some agricultural properties, where there is a swine production, it happens the readiness of these residues, being characterized in a great energy potential. In this work it was objectified to determine the cost and viability of electricity production using biogas as fuel an engine generator. (author)

  18. Megagauss field generation for high-energy-density plasma science experiments.

    Energy Technology Data Exchange (ETDEWEB)

    Rovang, Dean Curtis; Struve, Kenneth William; Porter, John Larry Jr.

    2008-10-01

    There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs.

  19. Virtual reality and motor rehabilitation of the upper limb after stroke: a generation of progress?

    Science.gov (United States)

    Lucca, Lucia Francesca

    2009-11-01

    To review the rationale, criteria of application, potentialities and limits of the available procedures for upper limb rehabilitation in virtual reality setups. Classification of the available virtual reality setups and comparison among published studies, with focus on the criteria of motor impairment and recovery assessment, rehabilitation procedures, and efficacy. The studies completed to date support application of virtual reality methods in the treatment of the paretic upper limb after stroke, but the superiority of virtual reality methods in comparison with conventional procedures currently in use is still unproven. Larger samples, adequate controlled study design and follow-up, greater homogeneity in the selection criteria and parameters measuring severity of stroke, motor impairment and recovery are necessary.

  20. Integral equation for electrostatic waves generated by a point source in a spatially homogeneous magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Podesta, John J. [Space Science Institute, Boulder, Colorado 80301 (United States)

    2012-08-15

    The electric field generated by a time varying point charge in a three-dimensional, unbounded, spatially homogeneous plasma with a uniform background magnetic field and a uniform (static) flow velocity is studied in the electrostatic approximation which is often valid in the near field. For plasmas characterized by Maxwell distribution functions with isotropic temperatures, the linearized Vlasov-Poisson equations may be formulated in terms of an equivalent integral equation in the time domain. The kernel of the integral equation has a relatively simple mathematical form consisting of elementary functions such as exponential and trigonometric functions (sines and cosines), and contains no infinite sums of Bessel functions. Consequently, the integral equation is amenable to numerical solutions and may be useful for the study of the impulse response of magnetized plasmas and, more generally, the response to arbitrary waveforms.

  1. A microfluidic chip for generating reactive plasma at gas-gas interface formed in laminar flow

    Science.gov (United States)

    Hashimoto, Masahiro; Tsukasaki, Katsuki; Kumagai, Shinya; Sasaki, Minoru

    2015-01-01

    A gas-gas interface is used for generating a localized reactive plasma flow at an atmospheric pressure. A microfluidic chip is fabricated as the reactor integrating a small plasma source located upstream. Within a Y-shaped microchannel, a discharging gas flows with a chemical gas. Owing to the small width of the microchannel, the gas flow is stabilized in a laminar flow. The resultant gas-gas interface is formed in the area where two gases flow facing each other activating the chemical gas through the energetic species in the discharging gas. A characteristic stream pattern is observed as the etching profile of a carbon film with a sub-µm sharp step change that can be explained by the spatial distribution of the reactive oxygen. This etching profile is different from that obtained when plasma discharging occurs near the channel exit being affected by the turbulent flow.

  2. Extreme ultraviolet emission from dense plasmas generated with sub-10-fs laser pulses

    CERN Document Server

    Osterholz, J; Cerchez, M; Fischer, T; Hemmers, D; Hidding, B; Pipahl, A; Pretzler, G; Rose, S J; Willi, O

    2008-01-01

    The extreme ultraviolet (XUV) emission from dense plasmas generated with sub-10-fs laser pulses with varying peak intensities up to 3*10^16 W/cm^2 is investigated for different target materials. K shell spectra are obtained from low Z targets (carbon and boron nitride). In the spectra a series limit for the hydrogen and helium like resonance lines is observed indicating that the plasma is at high density and pressure ionization has removed the higher levels. In addition, L shell spectra from titanium targets were obtained. Basic features of the K and L shell spectra are reproduced with computer simulations. The calculations include hydrodynamic simulation of the plasma expansion and collisional radiative calculations of the XUV emission.

  3. Analysis of Unbalanced Magnetic Pull in Wound Rotor Induction Machines using Finite Element Analysis – Transient, Motoring and Generating Modes

    DEFF Research Database (Denmark)

    Dorrell, David G.; Hermann, Alexander Niels August; Jensen, Bogi Bech

    2013-01-01

    There has been much literature on unbalanced magnetic pull in various types of electrical machine. This can lead to bearing wear and additional vibrations in the machine. In this paper a wound rotor induction is studied. Finite element analysis studies are conducted when the rotor has 10 % rotor...... eccentricity. The operating conditions are varied so that transient, motoring and doubly-fed induction generator modes are studied. This allows greater understanding of the radial forces involved. Wound rotor induction machines exhibit higher unbalanced magnetic pull than cage induction machines so...

  4. Gravity-dependent estimates of object mass underlie the generation of motor commands for horizontal limb movements.

    Science.gov (United States)

    Crevecoeur, F; McIntyre, J; Thonnard, J-L; Lefèvre, P

    2014-07-15

    Moving requires handling gravitational and inertial constraints pulling on our body and on the objects that we manipulate. Although previous work emphasized that the brain uses internal models of each type of mechanical load, little is known about their interaction during motor planning and execution. In this report, we examine visually guided reaching movements in the horizontal plane performed by naive participants exposed to changes in gravity during parabolic flight. This approach allowed us to isolate the effect of gravity because the environmental dynamics along the horizontal axis remained unchanged. We show that gravity has a direct effect on movement kinematics, with faster movements observed after transitions from normal gravity to hypergravity (1.8g), followed by significant movement slowing after the transition from hypergravity to zero gravity. We recorded finger forces applied on an object held in precision grip and found that the coupling between grip force and inertial loads displayed a similar effect, with an increase in grip force modulation gain under hypergravity followed by a reduction of modulation gain after entering the zero-gravity environment. We present a computational model to illustrate that these effects are compatible with the hypothesis that participants partially attribute changes in weight to changes in mass and scale incorrectly their motor commands with changes in gravity. These results highlight a rather direct internal mapping between the force generated during stationary holding against gravity and the estimation of inertial loads that limb and hand motor commands must overcome. Copyright © 2014 the American Physiological Society.

  5. Harmonic generation by atomic and nanoparticle precursors in a ZnS laser ablation plasma

    Science.gov (United States)

    Oujja, M.; Lopez-Quintas, I.; Benítez-Cañete, A.; de Nalda, R.; Castillejo, M.

    2017-01-01

    Harmonic generation of a driving laser propagating across a laser ablation plasma serves for the diagnosis of multicomponent plumes. Here we study the contribution of atomic and nanoparticle precursors to the generation of coherent ultraviolet and vacuum ultraviolet light as low-order harmonics of the fundamental emission (1064 nm) of a Q-switched Nd:YAG laser in a nanosecond infrared ZnS laser ablation plasma. Odd harmonics from the 3rd up to the 9th order (118.2 nm) have been observed with distinct temporal and spatial characteristics which were determined by varying the delay between the ablation and driving nanosecond pulses and by spatially scanning the plasma with the focused driving beam propagating parallel to the target. At short distances from the target surface (≤1 mm), the harmonic intensity displays two temporal components peaked at around 250 ns and 10 μs. While the early component dies off quickly with increasing harmonic order and vanishes for the 9th order, the late component is notably intense for the 7th harmonic and is still clearly visible for the 9th. Spectral analysis of spontaneous plume emissions help to assign the origin of the two components. While the early plasma component is mainly constituted by neutral Zn atoms, the late component is mostly due to nanoparticles, which upon interaction with the driving laser are subject to breakup and ionization. With the aid of calculations of the phase matching integrals within the perturbative model of optical harmonic generation, these results illustrate how atom and nanoparticle populations, with differing temporal and spatial distributions within the ablation plasma, contribute to the nonlinear medium.

  6. Modeling laser produced plasmas with smoothed particle hydrodynamics for next generation advanced light sources

    Science.gov (United States)

    Holladay, Robert; Griffith, Alec; Murillo, Michael S.

    2016-10-01

    A computational model has been developed to study the evolution of a plasma generated by next-generation advanced light sources such as SLAC's LCLS and LANL's proposed MaRIE. Smoothed Particle Hydrodynamics (SPH) is used to model the plasma evolution because of the ease with which it handles the open boundary conditions and large deformations associated with these experiments. Our work extends the basic SPH method by utilizing a two-fluid model of an electron-ion plasma that also incorporates time dependent ionization and recombination by allowing the SPH fluid particles to have an evolving mass based on the mean ionization state of the plasma. Additionally, inter-species heating, thermal conduction, and electric fields are also accounted for. The effects of various initial conditions and model parameters will be presented, with the goal of using this framework to develop a model that can be used in the design and interpretation of future experiments. This work was supported by the Los Alamos National Laboratory Computational Physics Workshop.

  7. Iron plasma generation using a Nd:YAG laser pulse of several hundred picoseconds

    Science.gov (United States)

    Tamura, Jun; Kumaki, Masafumi; Kondo, Kotaro; Kanesue, Takeshi; Okamura, Masahiro

    2016-02-01

    We investigated the high intensity plasma generated by using a Nd:YAG laser to apply a laser-produced plasma to the direct plasma injection scheme. The capability of the source to generate high charge state ions strongly depends on the power density of the laser irradiation. Therefore, we focused on using a higher power laser with several hundred picoseconds of pulse width. The iron target was irradiated with the pulsed laser, and the ion current of the laser-produced iron plasma was measured using a Faraday cup and the charge state distribution was investigated using an electrostatic ion analyzer. We found that higher charge state iron ions (up to Fe21+) were obtained using a laser pulse of several hundred picoseconds in comparison to those obtained using a laser pulse of several nanoseconds (up to Fe19+). We also found that when the laser irradiation area was relatively large, the laser power was absorbed mainly by the contamination on the target surface.

  8. Treatment of gastric cancer cells with non-thermal atmospheric plasma generated in water

    CERN Document Server

    Chen, Zhitong; Cheng, Xiaoqian; Gjika, Eda; Keidar, Michael

    2016-01-01

    Non-thermal atmospheric plasma (NTAP) can be applied to living tissues and cells as a novel technology for cancer therapy. Even though studies report on the successful use of NTAP to directly irradiate cancer cells, this technology can cause cell death only in the upper 3-5 cell layers. We report on a NTAP argon solution generated in DI water for treating human gastric cancer cells (NCl-N87). Our findings showed that the plasma generated in DI water during a 30-minute treatment had the strongest affect in inducing apoptosis in cultured human gastric cancer cells. This result can be attributed to presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced in water during treatment. Furthermore, the data showed that elevated levels of RNS may play an even more significant role than ROS in the rate of apoptosis in gastric cancer cells.

  9. High density ultrashort relativistic positron beam generation by laser-plasma interaction

    Science.gov (United States)

    Gu, Y. J.; Klimo, O.; Weber, S.; Korn, G.

    2016-11-01

    A mechanism of high energy and high density positron beam creation is proposed in ultra-relativistic laser-plasma interaction. Longitudinal electron self-injection into a strong laser field occurs in order to maintain the balance between the ponderomotive potential and the electrostatic potential. The injected electrons are trapped and form a regular layer structure. The radiation reaction and photon emission provide an additional force to confine the electrons in the laser pulse. The threshold density to initiate the longitudinal electron self-injection is obtained from analytical model and agrees with the kinetic simulations. The injected electrons generate γ-photons which counter-propagate into the laser pulse. Via the Breit-Wheeler process, well collimated positron bunches in the GeV range are generated of the order of the critical plasma density and the total charge is about nano-Coulomb. The above mechanisms are demonstrated by particle-in-cell simulations and single electron dynamics.

  10. A 7 T Pulsed Magnetic Field Generator for Magnetized Laser Plasma Experiments

    Science.gov (United States)

    Hu, Guangyue; Liang, Yihan; Song, Falun; Yuan, Peng; Wang, Yulin; Zhao, Bin; Zheng, Jian

    2015-02-01

    A pulsed magnetic field generator was developed to study the effect of a magnetic field on the evolution of a laser-generated plasma. A 40 kV pulsed power system delivered a fast (~230 ns), 55 kA current pulse into a single-turn coil surrounding the laser target, using a capacitor bank of 200 nF, a laser-triggered switch and a low-impedance strip transmission line. A one-dimensional uniform 7 T pulsed magnetic field was created using a Helmholtz coil pair with a 6 mm diameter. The pulsed magnetic field was controlled to take effect synchronously with a nanosecond heating laser beam, a femtosecond probing laser beam and an optical Intensified Charge Coupled Device (ICCD) detector. The preliminary experiments demonstrate bifurcation and focusing of plasma expansion in a transverse magnetic field.

  11. High quality electron bunch generation with CO2-laser plasma accelerator

    CERN Document Server

    Zhang, L G; Xu, J C; Ji, L L; Zhang, X M; Wang, W P; Zhao, X Y; Yi, L Q; Yu, Y H; Shi, Y; Xu, T J; Xu, Z Z

    2014-01-01

    CO2 laser-driven electron acceleration is demonstrated with particle-in-cell simulation in low-density plasma. An intense CO2 laser pulse with long wavelength excites wakefield. The bubble behind it has a broad space to sustain a large amount of electrons before reaching its charge saturation limit. A transversely propagating inject pulse is used to induce and control the ambient electron injection. The accelerated electron bunch with total charge up to 10 nC and the average charge per energy interval of more than 0.6 nC/MeV are obtained. Plasma-based electron acceleration driven by intense CO2 laser provides a new potential way to generate high-charge electron bunch with low energy spread, which has broad applications, especially for X-ray generation by table-top FEL and bremsstrahlung.

  12. Fast ion generation and bulk plasma heating with three-ion ICRF scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Kazakov, Ye. O., E-mail: yevgen.kazakov@rma.ac.be; Van Eester, D.; Ongena, J.; Lerche, E.; Messiaen, A. [Laboratory for Plasma Physics, LPP-ERM/KMS, EUROfusion Consortium Member, Brussels (Belgium); Dumont, R. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2015-12-10

    Launching electromagnetic waves in the ion cyclotron range of frequencies (ICRF) is an efficient method of plasma heating, actively employed in most of fusion machines. ICRF has a number of important supplementary applications, including the generation of high-energy ions. In this paper, we discuss a new set of three-ion ICRF scenarios and the prospect of their use as a dedicated tool for fast ion generation in tokamaks and stellarators. A distinct feature of these scenarios is a strong absorption efficiency possible at very low concentrations of resonant minority ions (∼ 1% or even below). Such concentration levels are typical for impurities contaminating fusion plasmas. An alternative ICRF scenario for maximizing the efficiency of bulk D-T ion heating is suggested for JET and ITER tokamaks, which is based on three-ion ICRF heating of intrinsic Beryllium impurities.

  13. Fast ion generation and bulk plasma heating with three-ion ICRF scenarios

    Science.gov (United States)

    Kazakov, Ye. O.; Van Eester, D.; Dumont, R.; Ongena, J.; Lerche, E.; Messiaen, A.

    2015-12-01

    Launching electromagnetic waves in the ion cyclotron range of frequencies (ICRF) is an efficient method of plasma heating, actively employed in most of fusion machines. ICRF has a number of important supplementary applications, including the generation of high-energy ions. In this paper, we discuss a new set of three-ion ICRF scenarios and the prospect of their use as a dedicated tool for fast ion generation in tokamaks and stellarators. A distinct feature of these scenarios is a strong absorption efficiency possible at very low concentrations of resonant minority ions (˜ 1% or even below). Such concentration levels are typical for impurities contaminating fusion plasmas. An alternative ICRF scenario for maximizing the efficiency of bulk D-T ion heating is suggested for JET and ITER tokamaks, which is based on three-ion ICRF heating of intrinsic Beryllium impurities.

  14. Study of magnetic field expansion using a plasma generator for space radiation active protection

    Institute of Scientific and Technical Information of China (English)

    JIA Xiang-Hong; JIA Shao-Xia; XU Feng; BAI Yan-Qiang; WAN Jun; LIU Hong-Tao; JIANG Rui

    2013-01-01

    There are many active protecting methods including Electrostatic Fields,Confined Magnetic Field,Unconfined Magnetic Field and Plasma Shielding etc.for defending the high-energy solar particle events (SPE) and Galactic Cosmic Rays (GCR) in deep space exploration.The concept of using cold plasma to expand a magnetic field is the best one of all possible methods so far.The magnetic field expansion caused by plasma can improve its protective efficiency of space particles.One kind of plasma generator has been developed and installed into the cylindrical permanent magnet in the eccentric.A plasma stream is produced using a helical-shaped antenna driven by a radio-frequency (RF) power supply of 13.56 MHz,which exits from both sides of the magnet and makes the magnetic field expand on one side.The discharging belts phenomenon is similar to the Earth's radiation belt,but the mechanism has yet to be understood.A magnetic probe is used to measure the magnetic field expansion distributions,and the results indicate that the magnetic field intensity increases under higher increments of the discharge power.

  15. Laser-driven electron beamlines generated by coupling laser-plasma sources with conventional transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Antici, P. [Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Frascati, Via E. Fermi, 40, 00044 Frascati (Italy); SAPIENZA, University of Rome, Dip. SBAI, Via A. Scarpa 14, 00161 Rome (Italy); INFN - Sezione di Roma, c/o Dipartimento di Fisica - SAPIENZA, University of Rome, P.le Aldo Moro, 2 - 00185 Rome (Italy); Bacci, A.; Chiadroni, E.; Ferrario, M.; Rossi, A. R. [Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Frascati, Via E. Fermi, 40, 00044 Frascati (Italy); Benedetti, C. [University of Bologna and INFN - Bologna (Italy); Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L. [SAPIENZA, University of Rome, Dip. SBAI, Via A. Scarpa 14, 00161 Rome (Italy); INFN - Sezione di Roma, c/o Dipartimento di Fisica - SAPIENZA, University of Rome, P.le Aldo Moro, 2 - 00185 Rome (Italy); Serafini, L. [INFN-Milan and Department of Physics, University of Milan, Via Celoria 16, 20133 Milan (Italy)

    2012-08-15

    Laser-driven electron beamlines are receiving increasing interest from the particle accelerator community. In particular, the high initial energy, low emittance, and high beam current of the plasma based electron source potentially allow generating much more compact and bright particle accelerators than what conventional accelerator technology can achieve. Using laser-generated particles as injectors for generating beamlines could significantly reduce the size and cost of accelerator facilities. Unfortunately, several features of laser-based particle beams need still to be improved before considering them for particle beamlines and thus enable the use of plasma-driven accelerators for the multiple applications of traditional accelerators. Besides working on the plasma source itself, a promising approach to shape the laser-generated beams is coupling them with conventional accelerator elements in order to benefit from both a versatile electron source and a controllable beam. In this paper, we perform start-to-end simulations to generate laser-driven beamlines using conventional accelerator codes and methodologies. Starting with laser-generated electrons that can be obtained with established multi-hundred TW laser systems, we compare different options to capture and transport the beams. This is performed with the aim of providing beamlines suitable for potential applications, such as free electron lasers. In our approach, we have analyzed which parameters are critical at the source and from there evaluated different ways to overcome these issues using conventional accelerator elements and methods. We show that electron driven beamlines are potentially feasible, but exploiting their full potential requires extensive improvement of the source parameters or innovative technological devices for their transport and capture.

  16. Laser-driven electron beamlines generated by coupling laser-plasma sources with conventional transport systems

    Science.gov (United States)

    Antici, P.; Bacci, A.; Benedetti, C.; Chiadroni, E.; Ferrario, M.; Rossi, A. R.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Serafini, L.

    2012-08-01

    Laser-driven electron beamlines are receiving increasing interest from the particle accelerator community. In particular, the high initial energy, low emittance, and high beam current of the plasma based electron source potentially allow generating much more compact and bright particle accelerators than what conventional accelerator technology can achieve. Using laser-generated particles as injectors for generating beamlines could significantly reduce the size and cost of accelerator facilities. Unfortunately, several features of laser-based particle beams need still to be improved before considering them for particle beamlines and thus enable the use of plasma-driven accelerators for the multiple applications of traditional accelerators. Besides working on the plasma source itself, a promising approach to shape the laser-generated beams is coupling them with conventional accelerator elements in order to benefit from both a versatile electron source and a controllable beam. In this paper, we perform start-to-end simulations to generate laser-driven beamlines using conventional accelerator codes and methodologies. Starting with laser-generated electrons that can be obtained with established multi-hundred TW laser systems, we compare different options to capture and transport the beams. This is performed with the aim of providing beamlines suitable for potential applications, such as free electron lasers. In our approach, we have analyzed which parameters are critical at the source and from there evaluated different ways to overcome these issues using conventional accelerator elements and methods. We show that electron driven beamlines are potentially feasible, but exploiting their full potential requires extensive improvement of the source parameters or innovative technological devices for their transport and capture.

  17. Specular Reflectivity and Hot-Electron Generation in High-Contrast Relativistic Laser-Plasma Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Gregory Elijah [The Ohio State Univ., Columbus, OH (United States)

    2013-01-01

    Ultra-intense laser (> 1018 W/cm2) interactions with matter are capable of producing relativistic electrons which have a variety of applications in state-of-the-art scientific and medical research conducted at universities and national laboratories across the world. Control of various aspects of these hot-electron distributions is highly desired to optimize a particular outcome. Hot-electron generation in low-contrast interactions, where significant amounts of under-dense pre-plasma are present, can be plagued by highly non-linear relativistic laser-plasma instabilities and quasi-static magnetic field generation, often resulting in less than desirable and predictable electron source characteristics. High-contrast interactions offer more controlled interactions but often at the cost of overall lower coupling and increased sensitivity to initial target conditions. An experiment studying the differences in hot-electron generation between high and low-contrast pulse interactions with solid density targets was performed on the Titan laser platform at the Jupiter Laser Facility at Lawrence Livermore National Laboratory in Livermore, CA. To date, these hot-electrons generated in the laboratory are not directly observable at the source of the interaction. Instead, indirect studies are performed using state-of-the-art simulations, constrained by the various experimental measurements. These measurements, more-often-than-not, rely on secondary processes generated by the transport of these electrons through the solid density materials which can susceptible to a variety instabilities and target material/geometry effects. Although often neglected in these types of studies, the specularly reflected light can provide invaluable insight as it is directly influenced by the interaction. In this thesis, I address the use of (personally obtained) experimental specular reflectivity measurements to indirectly study hot-electron generation in the context of high-contrast, relativistic

  18. Measurement of stability of electron beam generated by laser-driven plasma-based accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, S; Miura, E; Koyama, K; Kato, S [National Institute of Advanced Industrial Science and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)], E-mail: shi-masuda@aist.go.jp

    2008-05-01

    Quasi-monoenergetic electron beams with the energy of 30-80 MeV and large number of electrons more than 10{sup 8} were produced by focusing a 8TW, 50 fs Ti:sapphire laser pulse onto 1.6-1.9 x 10{sup 19} cm{sup -3} plasmas. Stability of the quasi-monoenergetic electron beam generation was evaluated using an in-situ observation system for the electron beam diagnostics.

  19. Efficiency of pulse high-current generator energy transfer into plasma liner energy

    Science.gov (United States)

    Oreshkin, V. I.

    2013-08-01

    The efficiency of capacitor-bank energy transfer from a high-current pulse generator into kinetic energy of a plasma liner has been analyzed. The analysis was performed using a model including the circuit equations and equations of the cylindrical shell motion. High efficiency of the energy transfer into kinetic energy of the liner is shown to be achieved only by a low-inductance generator. We considered an "ideal" liner load in which the load current is close to zero in the final of the shell compression. This load provides a high (up to 80%) efficiency of energy transfer and higher stability when compressing the liner.

  20. High-harmonic generation from plasma mirrors at kilohertz repetition rate

    OpenAIRE

    Quéré, Fabien

    2011-01-01

    International audience; We report the first demonstration of high-harmonic generation from plasma mirrors at a 1 kHz repetition rate. Harmonics up to nineteenth order are generated at peak intensities close to 1018 W=cm2 by focusing 1 mJ, 25 fs laser pulses down to 1:7 μm FWHM spot size without any prior wavefront correction onto a moving target. We minimize target surface motion with respect to the laser focus using online interferometry to ensure reproducible interaction conditions for ever...

  1. Micro generation of electricity with gasification gas in a engine generator in dual mode; Microgeracao de eletricidade com gas de gaseificacao num motor gerador dual

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcelo Jose da; Souza, Samuel Nelson Melegari de; Souza, Abel Alves de; Ricieri, Reinaldo P. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PE (Brazil)], E-mail: marcelo_js07@hotmail.com

    2010-07-01

    Among the alternatives to the increase of world energy demand the use of biomass as energy source is one of the most promising as it contributes to reducing emissions of carbon dioxide in the atmosphere. Gasification is a process technology of biomass energy in a gaseous biofuel. The fuel gas got a low calorific value that can be used in diesel engine in dual mode for power generation in isolated communities. This study aimed to evaluate the reduction in the consumption of oil diesel an engine generator, using gas from gasification of wood. The engine generator brand used, it was a BRANCO, with direct injection power of 10 hp and mated to an electric generator 5,5 kW. The fuel gas was produced in a gasifier type co-current. The engine generator was put on load system from 0.5 kW to 3.5 kW through electric bank of heaters. For the oil diesel savings, the gas was injected mixed with intake air, as the oil diesel was normally injected by the injector of the engine (motor dual). The consumption od diesel was measured diesel by means of a precision scale. It was concluded that the engine converted to dual mode when using the gas for the gasification of wood showed a decrease in diesel consumption by up to 57%. (author)

  2. Plasmas generated by ultra-violet light rather than electron impact

    Energy Technology Data Exchange (ETDEWEB)

    Franklin, R. N. [Department of Astronomy and Physics, The Open University, Milton Keynes MK7 6AA (United Kingdom); Allen, J. E. [University College, University of Oxford, Oxford OX1 4BH, United Kingdom and OCIAM, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Thomas, D. M. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Benilov, M. S. [Departamento de Fisica, CCCEE, Universidade de Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2013-12-15

    We analyze, in both plane and cylindrical geometries, a collisionless plasma consisting of an inner region where generation occurs by UV illumination, and an un-illuminated outer region with no generation. Ions generated in the inner region flow outwards through the outer region and into a wall. We solve for this system's steady state, first in the quasi-neutral regime (where the Debye length λ{sub D} vanishes and analytic solutions exist) and then in the general case, which we solve numerically. In the general case, a double layer forms where the illuminated and un-illuminated regions meet, and an approximately quasi-neutral plasma connects the double layer to the wall sheath; in plane geometry, the ions coast through the quasi-neutral section at slightly more than the Bohm speed c{sub s}. The system, although simple, therefore has two novel features: a double layer that does not require counter-streaming ions and electrons, and a quasi-neutral plasma where ions travel in straight lines with at least the Bohm speed. We close with a précis of our asymptotic solutions of this system, and suggest how our theoretical conclusions might be extended and tested in the laboratory.

  3. Study on the Generation Characteristics of Dielectric Barrier Discharge Plasmas on Water Surface

    Science.gov (United States)

    Liu, Wenzheng; Li, Chuanhui

    2014-01-01

    A new contact glow discharge electrode on the surface of water was designed and employed in this study. Because of the strong field strength in the small air gap formed by the electrode and the water surface, glow discharge plasmas were generated and used to treat waste water. The electric field distribution of the designed electrode model was simulated by MAXWELL 3D® simulation software, and the discharge parameters were measured. Through a series of experiments, we investigated the impact of optimal designs, such as the dielectric of the electrode, immersion depths, and curvature radii of the electrode on the generation characteristics of plasmas. In addition, we designed an equipotential multi-electrode configuration to treat a Methyl Violet solution and observe the discoloration effect. The experimental and simulation results indicate that the designed electrodes can realize glow discharge with a relative low voltage, and the generated plasmas covered a large area and were in stable state. The efficiency of water treatment is improved and optimized with the designed electrodes.

  4. Observation of magnetic field generation via the Weibel instability in interpenetrating plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Huntington, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fiuza, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zylstra, A. B. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Drake, R. P. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Atmospheric, Oceanic, and Space Sciences; Froula, D. H. [Univ. of Rochester, NY (United States). Physics Dept. and Lab. for Laser Energetics; Gregori, G. [Univ. of Oxford (United Kingdom). Dept. of Physics; Kugland, N. L. [Lam Research Corp., Fremont, CA (United States); Kuranz, C. C. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Atmospheric, Oceanic, and Space Sciences; Levy, M. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Li, C. K. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Meinecke, J. [Univ. of Oxford (United Kingdom). Dept. of Physics; Morita, T. [Osaka Univ. (Japan). Inst. of Laser Engineering; Petrasso, R. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Plechaty, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Remington, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sakawa, Y. [Osaka Univ. (Japan). Inst. of Laser Engineering; Spitkovsky, A. [Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences; Takabe, H. [Osaka Univ. (Japan). Inst. of Laser Engineering; Park, H.-S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-19

    Collisionless shocks can be produced as a result of strong magnetic fields in a plasma flow, and therefore are common in many astrophysical systems. The Weibel instability is one candidate mechanism for the generation of su fficiently strong fields to create a collisionless shock. Despite their crucial role in astrophysical systems, observation of the magnetic fields produced by Weibel instabilities in experiments has been challenging. Using a proton probe to directly image electromagnetic fields, we present evidence of Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows from laser-driven laboratory experiments. Three-dimensional particle-in-cell simulations reveal that the instability effi ciently extracts energy from the plasma flows, and that the self-generated magnetic energy reaches a few percent of the total energy in the system. Furthermore, this result demonstrates an experimental platform suitable for the investigation of a wide range of astrophysical phenomena, including collisionless shock formation in supernova remnants, large-scale magnetic field amplification, and the radiation signature from gamma-ray bursts.

  5. Helium-3 Generation from the Interaction of Deuterium Plasma inside a Hydrogenated Lattice: Red Fusion

    Science.gov (United States)

    Leal-Quiros, Edbertho; Leal-Escalante, David A.

    2015-03-01

    Helium-3 has been created in a nuclear fusion reaction by fusing deuterium ions from deuterium plasma with hydrogen ions in a “RED” (the Spanish word for net) or crystal lattice, a method we called red fusion ("Fusion en la red cristalina"), because is a new method to make nuclear fusion reaction. In this paper, it will be show the experimental results where the helium-3 has been generated for the first time in this kind of new method to confine deuterium and hydrogen inside the RED or lattice of the hydrogenated crystal and that confinement inside the RED facilitated overcoming the Coulomb barrier between them and helium-3 and phonons are produced in this fusion reaction. The results of a long time research in which helium-3, has been created in a fusion reaction inside the lattice or RED of the crystal that contained hydrogen after adequate interaction of deuterium plasma at appropriate high temperature and magnetic confinement of the Mirror/Cusp Plasma Machine at Polytechnic University of Puerto Rico, designed by the authors. Several mass spectra and visible light spectrum where the presence of helium-3 was detected are shown. The experiment was repeated more than 200 times showing always the generation of helium-3. In this experiment no gamma rays were detected. For this experiment several diagnostic instruments were used. The data collection with these control instrumentation are shown. Thus, it is an important new way to generate Helium-3. reserved.

  6. Torque Ripple Suppression Integrated Starter/Generator Control Strategy for Brushless Wound-Field Synchronous Motor

    Institute of Scientific and Technical Information of China (English)

    骆光照; 张围围; 杨南方; 马鹏; 刘卫国

    2012-01-01

    A flux linkage compensation field oriented control (FOC) method was proposed to suppress the speed and torque ripples of a hrusbless wound-fleld synchronous motor in its starting process. The starting process was analyzed and the model of wound-field synchronous electric machine was established. The change of field current of the electric machine was described mathematically for simplified exciter and rotate rectifier. Based on the traditional field control, the flux linkage compensation was introduced in d-axis current to counteract the flux ripple. Some simulation and preliminary experiments were implemented. The results show that the proposed method is feasible and effective.

  7. Magnetic loop generation by collisionless gravitationally bound plasmas in axisymmetric tori.

    Science.gov (United States)

    Cremaschini, Claudio; Stuchlík, Zdeněk

    2013-04-01

    Current-carrying string loops are adopted in astrophysics to model the dynamics of isolated flux tubes of magnetized plasma expected to arise in the gravitational field of compact objects, such as black holes. Recent studies suggest that they could provide a framework for the acceleration and collimation of jets of plasma observed in these systems. However, the problem remains of the search of physical mechanisms which can consistently explain the occurrence of such plasma toroidal structures characterized by nonvanishing charge currents and are able to self-generate magnetic loops. In this paper, the problem is addressed in the context of Vlasov-Maxwell theory for nonrelativistic collisionless plasmas subject to both gravitational and electromagnetic fields. A kinetic treatment of quasistationary axisymmetric configurations of charged particles exhibiting epicyclic motion is obtained. Explicit solutions for the species equilibrium phase-space distribution function are provided. These are shown to have generally a non-Maxwellian character and to be characterized by nonuniform fluid fields and temperature anisotropy. Calculation of the relevant fluid fields and analysis of the Ampere equation then show the existence of nonvanishing current densities. As a consequence, the occurrence of a kinetic dynamo is proved, which can explain the self-generation of both azimuthal and poloidal magnetic fields by the plasma itself. This mechanism can operate in the absence of instabilities, turbulence, or accretion phenomena and is intrinsically kinetic in character. In particular, several kinetic effects contribute to it, identified here with finite Larmor radius, diamagnetic and energy-correction effects together with temperature anisotropy, and non-Maxwellian features of the equilibrium distribution function.

  8. Studies of extreme ultraviolet emission from laser produced plasmas, as sources for next generation lithography

    Science.gov (United States)

    Cummins, Thomas

    The work presented in this thesis is primarily concerned with the optimisation of extreme ultraviolet (EUV) photoemission around 13.5 nm, from laser produced tin (Sn) plasmas. EUV lithography has been identified as the leading next generation technology to take over from the current optical lithography systems, due to its potential of printing smaller feature sizes on integrated circuits. Many of the problems hindering the implementation of EUV lithography for high volume manufacturing have been overcome during the past 20 years of development. However, the lack of source power is a major concern for realising EUV lithography and remains a major roadblock that must be overcome. Therefore in order to optimise and improve the EUV emission from Sn laser plasma sources, many parameters contributing to the make-up of an EUV source are investigated. Chapter 3 presents the results of varying several different experimental parameters on the EUV emission from Sn laser plasmas. Several of the laser parameters including the energy, gas mixture, focusing lens position and angle of incidence are changed, while their effect on the EUV emission is studied. Double laser pulse experiments are also carried out by creating plasma targets for the main laser pulse to interact with. The resulting emission is compared to that of a single laser pulse on solid Sn. Chapter 4 investigates tailoring the CO2 laser pulse duration to improve the efficiency of an EUV source set-up. In doing so a new technique for shortening the time duration of the pulse is described. The direct effects of shortening the CO2 laser pulse duration on the EUV emission from Sn are then studied and shown to improve the efficiency of the source. In Chapter 5 a new plasma target type is studied and compared to the previous dual laser experiments. Laser produced colliding plasma jet targets form a new plasma layer, with densities that can be optimised for re-heating with the main CO2 laser pulse. Chapter 6 will present

  9. Generation of complex motor patterns in american grasshopper via current-controlled thoracic electrical interfacing.

    Science.gov (United States)

    Giampalmo, Susan L; Absher, Benjamin F; Bourne, W Tucker; Steves, Lida E; Vodenski, Vassil V; O'Donnell, Peter M; Erickson, Jonathan C

    2011-01-01

    Micro-air vehicles (MAVs) have attracted attention for their potential application to military applications, environmental sensing, and search and rescue missions. While progress is being made toward fabrication of a completely human-engineered MAV, another promising approach seeks to interface to, and take control of, an insect's nervous system. Cyborg insects take advantage of their innate exquisite loco-motor, navigation, and sensing abilities. Recently, several groups have demonstrated the feasibility of radio-controlled flight in the hawkmoth and beetle via electrical neural interfaces. Here, we report a method for eliciting the "jump" response in the American grasshopper (S. Americana). We found that stimulating the metathoracic T3 ganglion with constant-current square wave pulses with amplitude 186 ± 40 μA and frequency 190 ± 13 Hz reproducibly evoked (≥95% success rate) the desired motor activity in N=3 test subjects. To the best of our knowledge, this is the first report of an insect cyborg with a synchronous neuromuscular system.

  10. Sporadic hereditary motor and sensory neuropathies: Advances in the diagnosis using next generation sequencing technology.

    Science.gov (United States)

    Fallerini, Chiara; Carignani, Giulia; Capoccitti, Giorgio; Federico, Antonio; Rufa, Alessandra; Pinto, Anna Maria; Rizzo, Caterina Lo; Rossi, Alessandro; Mari, Francesca; Mencarelli, Maria Antonietta; Giannini, Fabio; Renieri, Alessandra

    2015-12-15

    Hereditary motor and sensory neuropathies (HMSN) are genetically heterogeneous disorders affecting peripheral motor and sensory functions. Many different pathogenic variants in several genes involved in the demyelinating, the axonal and the intermediate HMSN forms have been identified, for which all inheritance patterns have been described. The mutation screening currently available is based on Sanger sequencing and is time-consuming and relatively expensive due to the high number of genes involved and to the absence of mutational hot spots. To overcome these limitations, we have designed a custom panel for simultaneous sequencing of 28 HMSN-related genes. We have applied this panel to three representative patients with variable HMSN phenotype and uncertain diagnostic classifications. Using our NGS platform we rapidly identified three already described pathogenic heterozygous variants in MFN2, MPZ and DNM2 genes. Here we show that our pre-custom platform allows a fast, specific and low-cost diagnosis in sporadic HMSN cases. This prompt diagnosis is useful for providing a well-timed treatment, establishing a recurrence risk and preventing further investigations poorly tolerated by patients and expensive for the health system. Importantly, our study illustrates the utility and successful application of NGS to mutation screening of a Mendelian disorder with extreme locus heterogeneity.

  11. Occurrence and location of concentrated load and generator regions observed by Cluster in the plasma sheet

    Directory of Open Access Journals (Sweden)

    M. Hamrin

    2009-11-01

    Full Text Available Here, and in a companion paper by Hamrin et al. (2009 [Scale size and life time of energy conversion regions observed by Cluster in the plasma sheet], we investigate localized energy conversion regions (ECRs in the Earth's plasma sheet. In total we have studied 151 ECRs within 660 h of plasma sheet data from the summer and fall of 2001 when Cluster was close to apogee at an altitude of about 15–20 RE. Cluster offers appropriate conditions for the investigation of energy conversion by the evaluation of the power density, E·J, where E is the electric field and J the current density. From the sign of the power density, we have identified more than three times as many Concentrated Load Regions (CLRs as Concentrated Generator Regions (CGRs. We also note that the CLRs appear to be stronger. To our knowledge, these are the first in situ observations confirming the general notion of the plasma sheet, on the average, behaving as a load. At the same time the plasma sheet appears to be highly structured, with energy conversion occurring in both directions between the fields and the particles. From our data we also find that the CLRs appear to be located closer to the neutral sheet, while CGRs prefer locations towards the plasma sheet boundary layer (PSBL. For both CLRs and CGRs, E and J in the GSM y (cross-tail direction dominate the total power density, even though the z contribution occasionally can be significant. The prevalence of the y-direction seems to be weaker for the CGRs, possibly related to a higher fluctuation level near the PSBL.

  12. Outlook for the use of microsecond plasma opening switches to generate high-power nanosecond current pulses

    Science.gov (United States)

    Dolgachev, G. I.; Maslennikov, D. D.; Ushakov, A. G.

    2006-12-01

    An analysis is made of the current break process in microsecond plasma opening switches and their possible application in high-current generators. Necessary conditions are determined for generating megavolt pulses in the erosion mode of a plasma opening switch with the gap insulated by an external magnetic field. Under these conditions, efficient sharpening of high-power submegampere current pulses can be achieved. The possibility of using plasma opening switches operating at voltages of 5 6 MV to generate X-ray and gamma emission is discussed. The main operating and design parameters of a six-module plasma opening switch with a current pulse amplitude of 3.7 MA and voltage of 4 6 MV for use in the MOL generator, which is the prototype of one of the 24 modules of the projected Baikal multimegajoule generator, are estimated by using the available scalings.

  13. Low-photon-energy plasma flash x-ray generator (LPFXG-2002)

    Science.gov (United States)

    Komatsu, Makoto; Sato, Eiichi; Hayasi, Yasuomi; Usuki, Tatsumi; Sato, Koetsu; Tanaka, Etsuro; Mori, Hidezo; Ojima, Hidenori; Takayama, Kazuyoshi; Ido, Hideaki

    2003-07-01

    In this study, we have made a low photon energy flash x-ray generator with a titanium target and have measured the radiographic characteristics. The flash x-ray generator consists of a high-voltage power supply, a high-voltage condenser, a turbo molecular pump and a flash x-ray tube. The condenser is charged up to about 30 kV, and the electric charges in the condenser are discharged to the tube after triggering the cathode. The linear plasma x-ray source forms from the target evaporation, and then the flash x-rays are generated from the plasma in the axial direction. K-series emission of titanium has been confirmed in experiments qualitatively and characteristics of the generator have been measured. K-series x-ray of titanium had a high resolution and enable us to take radiographs of a thin rabbit's ear clearly using the CR (Computed Radiography) system. The effect of titanium on the target of the soft flash x-ray tube has been indicated accordingly.

  14. A Tesla-pulse forming line-plasma opening switch pulsed power generator

    Science.gov (United States)

    Novac, B. M.; Kumar, R.; Smith, I. R.

    2010-10-01

    A pulsed power generator based on a high-voltage Tesla transformer which charges a 3.85 Ω/55 ns water-filled pulse forming line to 300 kV has been developed at Loughborough University as a training tool for pulsed power students. The generator uses all forms of insulation specific to pulsed power technology, liquid (oil and water), gas (SF6), and magnetic insulation in vacuum, and a number of fast voltage and current sensors are implemented for diagnostic purposes. A miniature (centimeter-size) plasma opening switch has recently been coupled to the output of the pulse forming line, with the overall system comprising the first phase of a program aimed at the development of a novel repetitive, table-top generator capable of producing 15 GW pulses for high power microwave loads. Technical details of all the generator components and the main experimental results obtained during the program and demonstrations of their performance are presented in the paper, together with a description of the various diagnostic tools involved. In particular, it is shown that the miniature plasma opening switch is capable of reducing the rise time of the input current while significantly increasing the load power. Future plans are outlined in the conclusions.

  15. Generation of high quality electron beams via ionization injection in a plasma wakefield accelerator

    Science.gov (United States)

    Vafaei-Najafabadi, Navid; Joshi, Chan; E217 SLAC Collaboration

    2016-10-01

    Ionization injection in a beam driven plasma wakefield accelerator has been used to generate electron beams with over 30 GeV of energy in a 130 cm of lithium plasma. The experiments were performed using the 3 nC, 20.35 GeV electron beam at the FACET facility of the SLAC National Accelerator Laboratory as the driver of the wakefield. The ionization of helium atoms in the up ramp of a lithium plasma were injected into the wake and over the length of acceleration maintained an emittance on the order of 30 mm-mrad, which was an order of magnitude smaller than the drive beam, albeit with an energy spread of 10-20%. The process of ionization injection occurs due to an increase in the electric field of the drive beam as it pinches through its betatron oscillations. Thus, this energy spread is attributed to the injection region encompassing multiple betatron oscillations. In this poster, we will present evidence through OSIRIS simulations of producing an injected beam with percent level energy spread and low emittance by designing the plasma parameters appropriately, such that the ionization injection occurs over a very limited distance of one betatron cycle. Work at UCLA was supported by the NSF Grant Number PHY-1415386 and DOE Grant Number DE-SC0010064. Work at SLAC was supported by DOE contract number DE-AC02-76SF00515. Simulations used the Hoffman cluster at UCLA.

  16. Mechanism analysis of radiation generated by the beam-plasma interaction in a vacuum diode

    Science.gov (United States)

    Zengchao, Ji; Shixiu, Chen; Shen, Gao

    2017-01-01

    When we were studying the vacuum switch, we found that the vacuum diode can radiate a broadband microwave. The vacuum diode is comprised of a cathode with a trigger device and planar anode, there is not a metallic bellows waveguide structure in this device, so the radiation mechanism of the vacuum diode is different from the plasma filled microwave device. It is hard to completely imitate the theory of the plasma filled microwave device. This paper analyzes the breakdown process of the vacuum diode, establishes the mathematical model of the radiating microwave from the vacuum diode. Based on the analysis of the dispersion relation in the form of a refractive index, the electromagnetic waves generated in the vacuum diode will resonate. The included angle between the direction of the electromagnetic radiation and the initial motion direction of electron beam is 45 degrees. The paper isolates the electrostatic effect from the beam-plasma interaction when the electromagnetic radiation occurs. According to above analyses, the dispersion relations of radiation are obtained by solving the wave equation. The dispersion curves are also obtained based on the theoretical dispersion relations. The theoretical dispersion curves are consistent with the actual measurement time-frequency maps of the radiation. Theoretical deduction and experiments indicate that the reason for microwave radiating from the vacuum diode can be well explained by the interaction of the electron beam and magnetized plasma. Supported by National Nature Science Foundation of China (No. 11075123), the Young Scientists Fund of Nature Science Foundation of China (No. 51207171).

  17. Monoenergetic proton emission from nuclear reaction induced by high intensity laser-generated plasma.

    Science.gov (United States)

    Torrisi, L; Cavallaro, S; Cutroneo, M; Giuffrida, L; Krasa, J; Margarone, D; Velyhan, A; Kravarik, J; Ullschmied, J; Wolowski, J; Szydlowski, A; Rosinski, M

    2012-02-01

    A 10(16) W∕cm(2) Asterix laser pulse intensity, 1315 nm at the fundamental frequency, 300 ps pulse duration, was employed at PALS laboratory of Prague, to irradiate thick and thin primary CD(2) targets placed inside a high vacuum chamber. The laser irradiation produces non-equilibrium plasma with deutons and carbon ions emission with energy of up to about 4 MeV per charge state, as measured by time-of-flight (TOF) techniques by using ion collectors and silicon carbide detectors. Accelerated deutons may induce high D-D cross section for fusion processes generating 3 MeV protons and 2.5 MeV neutrons, as measured by TOF analyses. In order to increase the mono-energetic proton yield, secondary CD(2) targets can be employed to be irradiated by the plasma-accelerated deutons. Experiments demonstrated that high intensity laser pulses can be employed to promote nuclear reactions from which characteristic ion streams may be developed. Results open new scenario for applications of laser-generated plasma to the fields of ion sources and ion accelerators.

  18. Monoenergetic proton emission from nuclear reaction induced by high intensity laser-generated plasma

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L. [INFN-LNS Via S. Sofia 44, 95123 Catania (Italy); Dip.to di Fisica, Universita di Messina, V.le F.S. D' Alcontres 31, 98166 S. Agata, Messina (Italy); Cavallaro, S.; Giuffrida, L. [INFN-LNS Via S. Sofia 44, 95123 Catania (Italy); Cutroneo, M. [Dip.to di Fisica, Universita di Messina, V.le F.S. D' Alcontres 31, 98166 S. Agata, Messina (Italy); Krasa, J.; Margarone, D.; Velyhan, A.; Ullschmied, J. [Institute of Physics, ASCR, v.v.i., 182 21 Prague 8 (Czech Republic); Kravarik, J. [Czech Technical University, Faculty of Electro-Engineering, Prague (Czech Republic); Wolowski, J.; Szydlowski, A.; Rosinski, M. [Institute of Plasma Physics and Laser Microfusion, IPPLM, 23 Hery Str., 01-497 Warsaw (Poland)

    2012-02-15

    A 10{sup 16} W/cm{sup 2} Asterix laser pulse intensity, 1315 nm at the fundamental frequency, 300 ps pulse duration, was employed at PALS laboratory of Prague, to irradiate thick and thin primary CD{sub 2} targets placed inside a high vacuum chamber. The laser irradiation produces non-equilibrium plasma with deutons and carbon ions emission with energy of up to about 4 MeV per charge state, as measured by time-of-flight (TOF) techniques by using ion collectors and silicon carbide detectors. Accelerated deutons may induce high D-D cross section for fusion processes generating 3 MeV protons and 2.5 MeV neutrons, as measured by TOF analyses. In order to increase the mono-energetic proton yield, secondary CD{sub 2} targets can be employed to be irradiated by the plasma-accelerated deutons. Experiments demonstrated that high intensity laser pulses can be employed to promote nuclear reactions from which characteristic ion streams may be developed. Results open new scenario for applications of laser-generated plasma to the fields of ion sources and ion accelerators.

  19. Observation of magnetic field generation via the Weibel instability in interpenetrating plasma flows

    CERN Document Server

    Huntington, C M; Ross, J S; Zylstra, A B; Drake, R P; Froula, D H; Gregori, G; Kugland, N L; Kuranz, C C; Levy, M C; Li, C K; Meinecke, J; Morita, T; Petrasso, R; Plechaty, C; Remington, B A; Ryutov, D D; Sakawa, Y; Spitkovsky, A; Takabe, H; Park, H -S

    2013-01-01

    As the ejecta from supernovae or other energetic astrophysical events stream through the interstellar media, this plasma is shaped by instabilities that generate electric and magnetic fields. Among these instabilities, the Weibel filamentation instability plays a particularly important role, as it can generate significant magnetic fields in an initially un-magnetized medium. It is theorized that these Weibel fields are responsible for the observed gamma-ray burst light curve, particle acceleration in shock waves, and for providing seed fields for larger-scale cosmological magnetic structures. While the presence of these instability-generated fields has been inferred from astrophysical observation and predicted in simulation, observation in experiments is challenging. Here we report direct observation of well-organized, large-amplitude, filamentary magnetic fields associated with the Weibel instability in a scaled laboratory experiment. The experimental images, captured with proton radiography, are shown to be...

  20. Generation of metal ions in the beam plasma produced by a forevacuum-pressure electron beam source

    Energy Technology Data Exchange (ETDEWEB)

    Tyunkov, A. V.; Yushkov, Yu. G., E-mail: YuYushkov@sibmail.com; Zolotukhin, D. B.; Klimov, A. S. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Savkin, K. P. [High Current Electronics Institute, Russian Academy of Sciences, Tomsk 634055 (Russian Federation)

    2014-12-15

    We report on the production of metal ions of magnesium and zinc in the beam plasma formed by a forevacuum-pressure electron source. Magnesium and zinc vapor were generated by electron beam evaporation from a crucible and subsequently ionized by electron impact from the e-beam itself. Both gaseous and metallic plasmas were separately produced and characterized using a modified RGA-100 quadrupole mass-spectrometer. The fractional composition of metal isotopes in the plasma corresponds to their fractional natural abundance.

  1. Servo motor control application research based on Xilinx FPGA system generator%Xilinx FPGA system generator 在伺服电机控制中的应用

    Institute of Scientific and Technical Information of China (English)

    程龙; 王卫兵; 王挺峰; 陈娟; 郭劲

    2015-01-01

    In order to avoid the FPGA language HDL code cumbersome,in this paper,by using Simulink integrated toolkit Xilinx FPGA unique System Generator module series,around three servo motor control application has carried on the simulation and experimental research.First of all,according to three kinds of servo motor control PWM signal waveform,the Simulink block diagram was established based on System Generator;Second,the Simulink simulation results correctly generated on the basis of HDL code;Then,using the ISE ModelSim simulation supporting software of HDL code test;Finally,on the basis of the ModelSim simulation results right code to load the FPGA hardware,and by using the ChipScope Pro PWM signal test.Accordance with the experimental results and simulation results,show that the method is simple,has a certain practical application value.%为了避免编写 FPGA 语言 HDL 代码的烦琐性,借助于 Simulink 集成工具箱中 Xilinx 系列 FPGA 独有的System Generator 模块,围绕3种伺服电机控制应用进行了仿真和实验研究。首先,根据3种伺服电机控制所需PWM 信号波形,利用 System Generator 建立 Simulink 仿真框图;其次,在 Simulink 仿真结果正确的基础上生成 HDL代码;然后,利用 ISE 的仿真配套软件 ModelSim 对 HDL 代码仿真测试;最后,在 ModelSim 仿真结果正确的基础上将代码载入 FPGA 硬件,并利用 ChipScope Pro 对 PWM 信号进行实验测试。实验结果与仿真结果的吻合,表明此方法简单易行,具有一定的实际应用价值。

  2. Astrophysics of magnetically collimated jets generated from laser-produced plasmas

    CERN Document Server

    Ciardi, A; Fuchs, J; Albertazzi, B; Riconda, C; Pépin, H; Portugall, O

    2012-01-01

    The generation of astrophysically relevant jets, from magnetically collimated, laser-produced plasmas, is investigated through three-dimensional, magneto-hydrodynamic simulations. We show that for laser intensities I ~ 10^12 - 10^14 W/cm^2, a magnetic field in excess of ~ 0.1 MG, can collimate the plasma plume into a prolate cavity bounded by a shock envelope with a standing conical shock at its tip, which re-collimates the flow into a super magneto-sonic jet beam. This mechanism is equivalent to astrophysical models of hydrodynamic inertial collimation, where an isotropic wind is focused into a jet by a confining circumstellar torus-like envelope. The results suggest an alternative mechanism for a large-scale magnetic field to produce jets from wide-angle winds. (abridged version)

  3. Generation of Cold Argon Plasma Jet at the End of Flexible Plastic Tube

    CERN Document Server

    Kostov, Konstantin G; Prysiazhnyi, Vadym

    2014-01-01

    This brief communication reports a new method for generation of cold atmospheric pressure plasma jet at the downstream end of a flexible plastic tube. The device consists of a small chamber where dielectric barrier discharge (DBD) is ignited in Argon. The discharge is driven by a conventional low frequency AC power supply. The exit of DBD reactor is connected to a commercial flexible plastic tube (up to 4 meters long) with a thin floating Cu wire inside. Under certain conditions an Ar plasma jet can be extracted from the downstream tube end and there is no discharge inside the plastic tube. The jet obtained by this method is cold enough to be put in direct contact with human skin without electric shock and can be used for medical treatment and decontamination.

  4. Generation and characterization of OH and O radicals by atmospheric pressure steam/oxygen plasma

    CERN Document Server

    Roy, N C; Alam, M K; Talukder, M R

    2016-01-01

    Atmospheric pressure steam/oxygen plasma is generated by a 88 Hz, 6kV AC power supply. The properties of the produced plasma are investigated by optical emission spectroscopy (OES). The relative intensity, rotational, vibrational, excitation temperatures and electron density are studied as function of applied voltage, electrode spacing and oxygen flow rate. The rotational and vibrational temperatures are determined simulating the bands with the aid of LIFBASE simulation software. The excitation temperature is obtained from the CuI transition taking non-thermal equilibrium condition into account employing intensity ratio method. The electron density is approximated from the H_{\\alpha} Stark broadening using the Voigt profile fitting method. It is observed that the rotational and vibrational temperatures are decreased with increasing electrode spacing and O2 flow rate, but increased with the applied voltage. The excitation temperature is found to increase with increasing applied voltage and O2 flow rate, but de...

  5. An All Solid-State Pulsed Power Generator for Plasma Immersion Ion Implantation (PⅢ)

    Institute of Scientific and Technical Information of China (English)

    LIU Kefu; QIU Jian; WU Yifan

    2009-01-01

    An all solid-state pulsed power generator for plasma immersion ion implantation (PⅢ) is described. The pulsed power system is based on a Marx circuit configuration and semi-conductor switches, which have many advantages in adjustable repetition frequency, pulse width modulation and long serving life compared with the conventional circuit category, tube-based technologies such as gridded vacuum tubes, thyratrons, pulse forming networks and transformers.The operation of PⅢ with pulse repetition frequencies up to 500 Hz has been achieved at a pulse voltage amplitude from 2 kV to 60 kV, with an adjustable pulse duration from 1 μs to 100 μs.The proposed system and its performance, as used to drive a plasma ion implantation chamber,axe described in detail on the basis of the experimental results.

  6. The third generation multi-purpose plasma immersion ion implanter for surface modification of materials

    CERN Document Server

    Tang Bao Yin; Wang Xiao Feng; Gan Kong Yin; Wang Song Yan; Chu, P K; Huang Nian Ning; Sun Hong

    2002-01-01

    The third generation multi-purpose plasma immersion ion implantation (PIII) equipment has been successfully used for research and development of surface modification of biomedical materials, metals and their alloys in the Southwest Jiaotong University. The implanter equipped with intense current, pulsed cathodic arc metal plasma sources which have both strong coating function and gas and metal ion implantation function. Its pulse high voltage power supply can provide big output current. It can acquire very good implantation dose uniformity. The equipment can both perform ion implantation and combine ion implantation with sputtering deposition and coating to form many kinds of synthetic surface modification techniques. The main design principles, features of important components and achievement of research works in recent time have been described

  7. Effects of laser polarizations on shock generation and shock ion acceleration in overdense plasmas

    Science.gov (United States)

    Kim, Young-Kuk; Kang, Teyoun; Jung, Moon Youn; Hur, Min Sup

    2016-09-01

    The effects of laser-pulse polarization on the generation of an electrostatic shock in an overdense plasma were investigated using particle-in-cell simulations. We found, from one-dimensional simulations, that total and average energies of reflected ions from a circular polarization- (CP) driven shock front are a few times higher than those from a linear polarization- (LP) driven one for a given pulse energy. Moreover, it was discovered that the pulse transmittance is the single dominant factor for determining the CP-shock formation, while the LP shock is affected by the plasma scale length as well as the transmittance. In two-dimensional simulations, it is observed that the transverse instability, such as Weibel-like instability, can be suppressed more efficiently by CP pulses.

  8. A compact, low cost Marx bank for generating capillary discharge plasmas

    Science.gov (United States)

    Dyson, A. E.; Thornton, C.; Hooker, S. M.

    2016-09-01

    We describe in detail a low power Compact Marx Bank (CMB) circuit that can provide 20 kV, 500 A pulses of approximately 100-200 ns duration. One application is the generation of capillary discharge plasmas of density ≈1018 cm-3 used in laser plasma accelerators. The CMB is triggered with a high speed solid state switch and gives a high voltage output pulse with a ns scale rise time into a 50 Ω load (coaxial cable) with run at shot repetition rates of ≳1 Hz. This low power requirement means that the circuit can easily be powered by a small lead acid battery and, therefore, can be floated relative to laboratory earth. The CMB is readily scalable and pulses >45 kV are demonstrated in air discharges.

  9. Astrophysics of magnetically collimated jets generated from laser-produced plasmas.

    Science.gov (United States)

    Ciardi, A; Vinci, T; Fuchs, J; Albertazzi, B; Riconda, C; Pépin, H; Portugall, O

    2013-01-11

    The generation of astrophysically relevant jets, from magnetically collimated, laser-produced plasmas, is investigated through three-dimensional, magnetohydrodynamic simulations. We show that for laser intensities I∼10(12)-10(14) W cm(-2), a magnetic field in excess of ∼0.1  MG, can collimate the plasma plume into a prolate cavity bounded by a shock envelope with a standing conical shock at its tip, which recollimates the flow into a supermagnetosonic jet beam. This mechanism is equivalent to astrophysical models of hydrodynamic inertial collimation, where an isotropic wind is focused into a jet by a confining circumstellar toruslike envelope. The results suggest an alternative mechanism for a large-scale magnetic field to produce jets from wide-angle winds.

  10. En Route: next-generation laser-plasma-based electron accelerators; En Route: Elektronenbeschleuniger der naechsten Generation auf Laser-Plasma-Basis

    Energy Technology Data Exchange (ETDEWEB)

    Hidding, Bernhard

    2008-05-15

    Accelerating electrons to relativistic energies is of fundamental interest, especially in particle physics. Today's accelerator technology, however, is limited by the maximum electric fields which can be created. This thesis presents results on various mechanisms aiming at exploiting the fields in focussed laser pulses and plasma waves for electron acceleration, which can be orders of magnitude higher than with conventional accelerators. With relativistic, underdense laser-plasma-interaction, quasimonoenergetic electron bunches with energies up to {approx}50 MeV and normalized emittances of the order of 5mmmrad have been generated. This was achieved by focussing the {approx}80 fs, 1 J pulses of the JETI-laser at the FSU Jena to intensities of several 10{sup 19}W=cm{sup 2} into gas jets. The experimental observations could be explained via 'bubble acceleration', which is based on self-injection and acceleration of electrons in a highly nonlinear breaking plasma wave. For the rst time, this bubble acceleration was achieved explicitly in the self-modulated laser wakefield regime (SMLWFA). This quasimonoenergetic SMLWFA-regime stands out by relaxing dramatically the requirements on the driving laser pulse necessary to trigger bubble acceleration. This is due to self-modulation of the laser pulse in high-density gas jets, leading to ultrashort laser pulse fragments capable of initiating bubble acceleration. Electron bunches with durations

  11. Experimental Study of Plasma Under-liquid Electrolysis in Hydrogen Generation

    Institute of Scientific and Technical Information of China (English)

    严宗诚; 陈砺; 王红林

    2006-01-01

    The application and characteristics of relatively big volume plasma produced with cathodic glow discharges taking place across a gaseous envelope over the cathode which was dipped into electrolyte in hydrogen generation were studied. A critical investigation of the influence of methanol concentration and voltage across the circuit on the composition and power consumption per cubic meter of cathode liberating gas was carried out. The course of plasma under-liquid electrolysis has the typical characteristics of glow discharge electrolysis. The cathode liberating gas was in substantial excess of the Faraday law value. When the voltage across the circuit was equal to 550 V, the volume of cathodic gas with sodium carbonate solution was equal to 16.97 times the Faraday law value. The study showed that methanol molecules are more active than water molecules.The methanol molecules were decomposed at the plasma-catholyte interface by the radicals coming out the plasma mantle.Energy consumption per cubic meter of cathodic gases (WV) decreased while methanol concentration of the electrolytes increased. When methanol concentration equaled 5% (ψ), WV was 10.381×103 kJ/m3, less than the corresponding theoretic value of conventional water electrolysis method. The cathodic liberating gas was a mixture of hydrogen, carbon dioxide and carbon monoxide with over 95% hydrogen, if methanol concentration was more than 15% (ψ). The present research work revealed an innovative application of glow discharge and a new highly efficient hydrogen generation method, which depleted less resource and energy than normal electrolysis and is environmentally friendly.

  12. Advanced Thomson scattering system for high-flux linear plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Meiden, H. J. van der; Lof, A. R.; Berg, M. A. van den; Brons, S.; Eck, H. J. N. van; Koelman, P. M. J.; Koppers, W. R.; Kruijt, O. G.; Oyevaar, T.; Prins, P. R.; Rapp, J.; Scholten, J.; Smeets, P. H. M.; Star, G. van der; Zeijlmans van Emmichoven, P. A. [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Donne, A. J. H.; Schram, D. C. [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, Eindhoven (Netherlands); Naumenko, N. N. [IPh NASB, Minsk (Belarus); Tugarinov, S. N. [SRC TRINITI, Troitsk, Moscow Reg. (Russian Federation)

    2012-12-15

    An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f /3) transmission grating spectrometer equipped with an intensified charged coupled device camera. The system is able to measure electron density (n{sub e}) and temperature (T{sub e}) profiles close to the output of the plasma source and, at a distance of 1.25 m, just in front of a target. The detection system enables to measure 50 spatial channels of about 2 mm each, along a laser chord of 95 mm. By summing a total of 30 laser pulses (0.6 J, 10 Hz), an observational error of 3% in n{sub e} and 6% in T{sub e} (at n{sub e}= 9.4 Multiplication-Sign 10{sup 18} m{sup -3}) can be obtained. Single pulse Thomson scattering measurements can be performed with the same accuracy for n{sub e} > 2.8 Multiplication-Sign 10{sup 20} m{sup -3}. The minimum measurable density and temperature are n{sub e} < 1 Multiplication-Sign 10{sup 17} m{sup -3} and T{sub e} < 0.07 eV, respectively. In addition, using the Rayleigh peak, superimposed on the Thomson scattered spectrum, the neutral density (n{sub 0}) of the plasma can be measured with an accuracy of 25% (at n{sub 0}= 1 Multiplication-Sign 10{sup 20} m{sup -3}). In this report, the performance of the Thomson scattering system will be shown along with unprecedented accurate Thomson-Rayleigh scattering measurements on a low-temperature argon plasma expansion into a low-pressure background.

  13. Operating conditions for the generation of stable anode spot plasma in front of a positively biased electrode

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yeong-Shin; Lee, Yuna; Dang, Jeong-Jeung [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15

    Stability of an anode spot plasma, which is an additional high density plasma generated in front of a positively biased electrode immersed in ambient plasma, is a critical issue for its utilization to various types of ion sources. In this study, operating conditions for the generation of stable anode spot plasmas are experimentally investigated. Diagnostics of the bias current flowing into the positively biased electrode and the properties of ambient plasma reveal that unstable nature of the anode spot is deeply associated with the reduction of double layer potential between the anode spot plasma and the ambient plasma. It is found that stability of the anode spot plasma can be improved with increasing the ionization rate in ambient plasma so as to compensate the loss of electrons across the double layer or with enlarging the area of the biased electrode to prevent electron accumulation inside the anode spot. The results obtained from the present study give the guideline for operating conditions of anode spot plasmas as an ion source with high brightness.

  14. Discarded Motors Converted into Wind Driven Generator%废旧电机改装风力发电机

    Institute of Scientific and Technical Information of China (English)

    周郭牛; 蔡悦

    2012-01-01

    随着全球能源危机日益加剧,寻找一种新的能源迫在眉睫,风能以其取之方便、无污染等优点成为大家关注的焦点。根据电磁感应定律,利用风能推动桨叶带动电机旋转,从而输出电压,达到风能发电的目的。根据这个基本原理,可以利用电动车废旧电机制造成小型发电机,对解决一些偏远山区、海岛用电问题有一定的参考价值。%With the growing global energy crisis,looking for a new energy is extremely urgent.Wind energy becomes the focus of attention for its convenience and pollution-free.According to the law of electromagnetic induction,the use of wind energy to promote the blade drives motor rotation,and thus to output voltage to achieve the purpose of wind energy.According to this basic principle,the wasted motors of electric car can be used to produce small generators and solve certain problems in some remote mountainous areas and islands.

  15. Third Harmonic Generation of a Short Pulse Laser in a Tunnel Ionizing Plasma: Effect of Self-Defocusing

    OpenAIRE

    Niti Kant

    2013-01-01

    Third harmonic generation of a Gaussian short pulse laser in a tunnel ionizing plasma is investigated. A Gaussian short pulse laser propagating through a tunnel ionizing plasma generates third harmonic wave. Inhomogeneity of the electric field along the wavefront of the fundamental laser pulse causes more ionization along the axis of propagation while less ionization off axis, leading to strong density gradient with its maximum on the axis of propagation. The medium acts like a diverging lens...

  16. Analyzing the Relationship Between Car Generation and Severity of Motor-Vehicle Crashes in Denmark

    DEFF Research Database (Denmark)

    Rich, Jeppe; Prato, Carlo Giacomo; Hels, Tove

    2013-01-01

    .e., car’s first registration year) and injury severity sustained by car drivers involved in accidents in Denmark between 2004 and 2010. A generalized ordered logit model was estimated while controlling for several characteristics of the crash, the vehicle and the persons involved, and a sensitivity...... car market with remarkably high registration tax that causes potential buyers to hold longer onto old cars, the relationship between technological enhancements of vehicles and severity of crashes requires particular attention. The current study investigated the relationship between car generation (i...... analysis was performed to assess the effect of car generation on drivers’ injury severity. Results illustrate that newer car generations are associated to significantly lower probability of injury and fatality, and that replacing older cars with newer ones introduces significant and not to be overlooked...

  17. Analyzing the Relationship Between Car Generation and Severity of Motor-Vehicle Crashes in Denmark

    DEFF Research Database (Denmark)

    Rich, Jeppe; Prato, Carlo Giacomo; Hels, Tove;

    2013-01-01

    car market with remarkably high registration tax that causes potential buyers to hold longer onto old cars, the relationship between technological enhancements of vehicles and severity of crashes requires particular attention. The current study investigated the relationship between car generation (i.......e., car’s first registration year) and injury severity sustained by car drivers involved in accidents in Denmark between 2004 and 2010. A generalized ordered logit model was estimated while controlling for several characteristics of the crash, the vehicle and the persons involved, and a sensitivity...... analysis was performed to assess the effect of car generation on drivers’ injury severity. Results illustrate that newer car generations are associated to significantly lower probability of injury and fatality, and that replacing older cars with newer ones introduces significant and not to be overlooked...

  18. Next-generation sequencing as a powerful motor for advances in the biological and environmental sciences.

    Science.gov (United States)

    Faure, Denis; Joly, Dominique

    2015-04-01

    Next-generation sequencing (NGS) provides unprecedented insight into (meta)genomes, (meta)transcriptomes (cDNA) and (meta)barcodes of individuals, populations and communities of Archaea, Bacteria and Eukarya, as well as viruses. This special issue combines reviews and original papers reporting technical and scientific advances in genomics and transcriptomics of non-model species, as well as quantification and functional analyses of biodiversity using NGS technologies of the second and third generations. In addition, certain papers also exemplify the transition from Sanger to NGS barcodes in molecular taxonomy.

  19. Ablation of Barrett’s esophagus using the second-generation argon plasma coagulation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To investigate the efficacy and safety of the second-generation argon plasma coagulation (VIO APC) in ablation of Barrett’s esophagus. Methods Eighteen patients with Barrett’s esophagus (12 males, median age of 55 years, median length of 2.1 cm,1 low-grade dysplasia, 13 cases of short segment Barrett’s esophagus) received VIO APC, which was performed at a power setting of 40W and argon gas flow at 1.5-2.0 L/min, "forced" mode, in 1-3 sessions (mean 1.3). All the patients received treatment with hi...

  20. Isolated sub-fs XUV pulse generation in Mn plasma ablation.

    Science.gov (United States)

    Ganeev, R A; Witting, T; Hutchison, C; Frank, F; Tudorovskaya, M; Lein, M; Okell, W A; Zaïr, A; Marangos, J P; Tisch, J W G

    2012-11-05

    We report studies of high-order harmonic generation in laser-produced manganese plasmas using sub-4-fs drive laser pulses. The measured spectra exhibit resonant enhancement of a small spectral region of about 2.5 eV width around the 31st harmonic (~50eV). The intensity contrast relative to the directly adjacent harmonics exceeds one order of magnitude. This finding is in sharp contrast to the results reported previously for multi-cycle laser pulses [Physical Review A 76, 023831 (2007)]. Theoretical modelling suggests that the enhanced harmonic emission forms an isolated sub-femtosecond pulse.

  1. High-Power γ-Ray Flash Generation in Ultraintense Laser-Plasma Interactions

    Science.gov (United States)

    Nakamura, Tatsufumi; Koga, James K.; Esirkepov, Timur Zh.; Kando, Masaki; Korn, Georg; Bulanov, Sergei V.

    2012-05-01

    When high-intensity laser interaction with matter enters the regime of dominated radiation reaction, the radiation losses open the way for producing short pulse high-power γ-ray flashes. The γ-ray pulse duration and divergence are determined by the laser pulse amplitude and by the plasma target density scale length. On the basis of theoretical analysis and particle-in-cell simulations with the radiation friction force incorporated, optimal conditions for generating a γ-ray flash with a tailored overcritical density target are found.

  2. Iodine Determination by Microwave Plasma Torch Atomic Emission Spectrometer Coupled with Online Preconcentration Vapor Generation Technique

    Institute of Scientific and Technical Information of China (English)

    FEI Yan-qun; LUO Gui-min; FENG Guo-dong; CHEN Huan-wen; FEI Qiang; HUAN Yan-fu; JIN Qin-han

    2008-01-01

    This article focuses on iodine determination by microwave plasma torch atomic emission spectrometry (MPT-AES) coupled with online preconcentration vapor generation method.A new desolvation device,multistrand Nation dryer,was used as the substitute for condenser desolvation system.Some experimental conditions,such as preconcentration time,acidity of sample solution,rinsing solution acidity and dynamic linear range were investigated and optimized.The new desolvation system eliminates the problem of decreasing emission intensity of I(I) 206.238 nm line with the increase of working time on a conventional condenser desolvation system,thus greatly improving the reproducibility.

  3. A laser-generated plasma as a source of VUV continuum radiation for photoelectronic spectroscopy

    OpenAIRE

    Heckenkamp, Ch.; Heinzmann, Ulrich; Schönhense, G.; BURGESS.D.D; Thorne, A. P.; Wheaton, J. E. G.

    1981-01-01

    The feasibility of using laser-generated plasmas as VUV continuum sources for photoelectron spectroscopy has been demonstrated by measuring the spectral intensity distribution of the VUV continuum in the wavelength region from 79 to 43 nm by energy analysis of the photoelectrons ejected from argon atoms. The maximum photon flux obtained after reflection at a gold-coated spherical mirror was of the order of 10(11) photons nm(-1) per pulse at 50 nm for a laser energy of 830 mJ. The results show...

  4. Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications

    Science.gov (United States)

    Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.

    2014-03-01

    The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.

  5. Analysis of the comprehensive physical field for a new flywheel energy storage motor/generator on ships

    Science.gov (United States)

    Yu, Yali; Wang, Yuanxi; Zhang, Guosheng; Sun, Feng

    2012-03-01

    A novel flywheel energy storage (FES) motor/generator (M/G) was proposed for marine systems. The purpose was to improve the power quality of a marine power system (MPS) and strengthen the energy recycle. Two structures including the magnetic or non-magnetic inner-rotor were contrasted in the magnetostatic field by using finite element analysis (FEA). By optimally designing the size parameters, the average speed of FEA results of was 17 200 r/m, and the current was controlled between 62 and 68 A in the transient field. The electrical machine electromagnetism design was further optimized by the FEA in the temperature field, to find the local overheating point under the normal operation condition and provide guidance for the cooling system. Finally, it can be concluded from the comprehensive physical field analysis that the novel redundant structure M/G can improve the efficiency of the M/G and maintain the stability of the MPS.

  6. Safe and Stable Operation of Generator-motor%发电电动机的安全稳定运行

    Institute of Scientific and Technical Information of China (English)

    赵政

    2011-01-01

    本文基于抽水蓄能电站在电力系统中的重要性,从分析发电电动机的故障及事故入手,就发电电动机的参数和结构的合理选择、与水泵水轮机结构和参数的匹配、水泵水轮机调试和运行方式对发电电动机的影响、电站运行方式的合理选择、与厂房结构的设计协调、安装和运行维护、在线监测、寿命诊断等诸方面对发电电动机的运行稳定性进行论述.%Based on the importance of pumped storage project in power system, this paper describes the operation stability of motor generator considering failure and accident event frequency, reasonable generator parameter and structure option, well coordination with pump turbine structure and parameter, impact on generator by pump turbine debugging and operation mode, reasonable selection of operation mode of power plant, design harmony with structure of powerhouse,installation and operation maintenance, on-line monitoring, life diagnosis and other parameters, etc.

  7. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    Science.gov (United States)

    Kühn, S.; Bibinov, N.; Gesche, R.; Awakowicz, P.

    2010-01-01

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O3, correspondingly, are generated.

  8. A linear-field plasma jet for generating a brush-shaped laminar plume at atmospheric pressure

    Science.gov (United States)

    Li, Xuechen; Li, Jiyuan; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

    2016-06-01

    A linear-field plasma jet composed of line-to-plate electrodes is used to generate a large-scale brush-shaped plasma plume with flowing argon used as working gas. Through electrical measurement and fast photography, it is found that the plasma plume bridges the two electrodes for the discharge in the positive voltage half-cycle, which behaves like fast moving plasma bullets directed from the anode to the cathode. Compared with the positive discharge, the negative discharge only develops inside the nozzle and propagates much slower. Results also indicate that the gas temperature of the plume is close to room temperature, which is promising for biomedical application.

  9. Ion acceleration from intense laser-generated plasma: methods, diagnostics and possible applications

    Directory of Open Access Journals (Sweden)

    Torrisi Lorenzo

    2015-06-01

    Full Text Available Many parameters of non-equilibrium plasma generated by high intensity and fast lasers depend on the pulse intensity and the laser wavelength. In conditions favourable for the target normal sheath acceleration (TNSA regime the ion acceleration from the rear side of the target can be enhanced by increasing the thin foil absorbance through the use of nanoparticles and nanostructures promoting the surface plasmon resonance effect. In conditions favourable for the backward plasma acceleration (BPA regime, when thick targets are used, a special role is played by the laser focal position with respect to the target surface, a proper choice of which may result in induced self-focusing effects and non-linear acceleration enhancement. SiC detectors employed in the time-of-flight (TOF configuration and a Thomson parabola spectrometer permit on-line diagnostics of the ion streams emitted at high kinetic energies. The target composition and geometry, apart from the laser parameters and to the irradiation conditions, allow further control of the plasma characteristics and can be varied by using advanced targets to reach the maximum ion acceleration. Measurements using advanced targets with enhanced the laser absorption effect in thin films are presented. Applications of accelerated ions in the field of ion source, hadrontherapy and nuclear physics are discussed.

  10. Temporal evolution of linear kinetic Alfvén waves in inhomogeneous plasmas and turbulence generation

    Science.gov (United States)

    Goyal, Ravinder; Sharma, R. P.

    2016-07-01

    The coronal ion heating in the Sun is primarily considered due to Alfvén wave dissipation. The Hinode data which has provided strong evidence for the presence of Alfvén waves in the corona and in coronal loops, has lead laboratory investigations and numerical simulations of Alfvén wave propagation and damping. The inhomogeneous plasmas with steep density gradients can be employed to study such phenomenon in relatively shorter systems. This article presents a model for the propagation of Kinetic Alfvén waves (KAWs) in inhomogeneous plasma when the inhomogeneity is in transverse and parallel directions relative to the background magnetic field. The semi-analytical technique and numerical simulations have been performed to study the KAW dynamics when plasma inhomogeneity is incorporated in the dynamics. The model equations are solved in order to study the localization of KAW and their magnetic power spectrum which indicates the direct transfer of energy from lower to higher wave numbers as well as frequencies. The inhomogeneity scale lengths in both directions may control the nature of fluctuations and localization of the waves and play a very important role in the turbulence generation and its level. We present a theoretical study of the localization of KAWs, variations in magnetic field amplitude in time, and variation in the frequency spectra arising from inhomogeneities. The relevance of the model to space and laboratory observations is discussed.

  11. Plasma formation and dynamics in conical wire arrays in the Llampudken pulsed power generator

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, C. Gonzalo, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl; Valenzuela, Vicente, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl; Veloso, Felipe, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl; Favre, Mario, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl; Wyndham, Edmund, E-mail: gamunoz2f@uc.cl, E-mail: fveloso@fis.puc.cl [Instituto de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago (Chile)

    2014-12-15

    Plasma formation and dynamics from conical wire array is experimentally studied. Ablation from the wires is observed, forming plasma accumulation at the array axis and subsequently a jet outflow been expelled toward the top of the array. The arrays are composed by 16 equally spaced 25μ diameter tungsten wires. Their dimensions are 20mm height, with base diameters of 8mm and 16mm top diameter. The array loads are design to be overmassed, hence no complete ablation of the wires is observed during the current rise. The experiments have been carried out in the Llampudken. pulsed power generator (∼350kA in ∼350ns). Plasma dynamics is studied in both side-on and end-on directions. Laser probing (shadowgraphy) is achieved using a frequency doubled Nd:YAG laser (532nm, 12ps FWHM) captured by CCD cameras. Pinhole XUV imaging is captured using gated microchannel plate cameras with time resolution ∼5ns. Results on the jet velocity and the degree of collimation indicating the plausibility on the use of these jets as comparable to the study astrophysically produced jets are presented and discussed.

  12. High harmonic generation in underdense plasmas by intense laser pulses with orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Mendonça, J. T., E-mail: josetitomend@gmail.com [IPFN, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal and Instituto de Física, Universidade de São Paulo, 05508-090 São Paulo, SP (Brazil); Vieira, J., E-mail: jorge.vieira@ist.utl.pt [GoLP, IPFN, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal)

    2015-12-15

    We study high harmonic generation produced by twisted laser pulses, with orbital angular momentum in the relativistic regime, for pulse propagation in underdense plasma. We consider fast time scale processes associated with an ultra-short pulse, where the ion motion can be neglected. We use both analytical models and numerical simulations using a relativistic particle-in-cell code. The present description is valid for relativistic laser intensities, when the normalized field amplitude is much larger than one, a ≫ 1. We also discuss two distinct processes associated with linear and circular polarization. Using both analytical solutions and particle-in-cell simulations, we are able to show that, for laser pulses in a well defined Laguerre-Gauss mode, angular momentum conservation is observed during the process of harmonic generation. Intensity modulation of the harmonic spectrum is also verified, as imposed by the nonlinear time-scale for energy transfer between different harmonics.

  13. Small-size plasma diode with a transparent internal cathode for neutron generation

    Science.gov (United States)

    Shikanov, A. E.; Vovchenko, E. D.; Kozlovskii, K. I.; Shatokhin, V. L.

    2015-01-01

    A discharge plasma system for neutron generation based on the concept of inertial electrostatic confinement is considered. The system is made in the form of a gas-filled (1-60 Pa) diode with a composite hollow cathode placed at its center symmetrically to an embracing hollow cylindrical anode. Preionization of the discharge gap and an original design of the electrode system with a transparent central part make it possible to initiate a pulse high-voltage (100-150 kV) volume discharge in the ion oscillation mode. Estimates of the neutron emission in such a deuterium-filled diode show the feasibility of generating a pulse with a neutron yield on the order of 105 in the reaction D( d, n)3He, which is confirmed in experiments with an optimized geometry of the electrodes.

  14. High quality electron bunch generation with CO2-laser-plasma interaction

    Science.gov (United States)

    Zhang, Lingang; Shen, Baifei; Xu, Jiancai; Ji, Liangliang; Zhang, Xiaomei; Wang, Wenpeng; Zhao, Xueyan; Yi, Longqing; Yu, Yahong; Shi, Yin; Xu, Tongjun; Xu, Zhizhan

    2015-02-01

    CO2 laser-driven electron acceleration in low-density plasma is demonstrated using particle-in-cell simulation. An intense CO2 laser pulse of long wavelength excites a wake bubble that has a large elongated volume for accelerating a large number of electrons before reaching the charge saturation limit. A transversely injected laser pulse is used to induce and control the electron injection. It is found that an electron bunch with total charge up to 10 nC and absolute energy spread less than 16 MeV can be obtained. As a result, the charge per energy interval of the bunch reaches up to 0.6 nC/MeV. Intense CO2-laser based electron acceleration can provide a new direction for generating highly charged electron bunches with low energy spread, which is of much current interest, especially for table-top X-ray generation.

  15. Optical properties of the atmospheric pressure helium plasma jet generated by alternative current (a.c.) power supply

    Science.gov (United States)

    Ilik, Erkan; Akan, Tamer

    2016-05-01

    In this work, an atmospheric pressure plasma jet (APPJ) was produced to generate cold flowing post-discharge plasma of pure helium gas. The main aim of this study was to generate cold flowing APPJ of pure helium gas and to determine how their optical emission spectrum change influences varying different flow rates. Lengths of early, middle, and late post-discharge plasma (jet) regions and their fluctuations were determined, respectively. Then, ignition condition dependence of the post-discharge plasma for flow rate was specified at a constant voltage. Spectroscopic studies of an atmospheric pressure plasma jet of helium were presented via analyzing OH, N2, N2+, oxygen, and helium intensities for various flow rates.

  16. Numerical Study of Injection Mechanisms for Generation of Mono-Energetic Femtosecond Electron Bunch from the Plasma Cathode

    CERN Document Server

    Ohkubo, Takeru; Zhidkov, Alexei

    2005-01-01

    Acceleration gradients of up to the order of 100GV/m and mono-energetic electron bunch up to 200MeV have recently been observed in several plasma cathode experiments. However, mechanisms of self-injection in plasma are not sufficiently clarified, presently. In this study, we carried out 2D PIC simulation to reveal the mechanisms of mono-energetic femtosecond electron bunch generation. We found two remarkable conditions for the generation: electron density gradient at vacuum-plasma interface and channel formation in plasma. Steep electron density gradient (~ plasma wave length) causes rapid injection and produces an electron bunch with rather high charge and less than 100fs duration. The channel formation guides an injected laser pulse and decreases the threshold of laser self-focusing, which leads to high electric field necessary for wave-breaking injection.

  17. Evaluation of Novel Integrated Dielectric Barrier Discharge Plasma as Ozone Generator

    Directory of Open Access Journals (Sweden)

    Muhammad Nur

    2017-04-01

    Full Text Available This paper presents a characterization of an integrated ozone generator constructed by seven of reactors of Dielectric Barrier Discharge Plasma (DBDP. DBDP a has spiral-cylindrical configuration. Silence plasma produced ozone inside the DBDP reactor was generated by AC-HV with voltage up to 25 kV and maximum frequency of 23 kHz. As a source of ozone, dry air was pumped into the generator and controlled by valves system and a flowmeter. We found ozone concentration increased with the applied voltage, but in contrary, the concentration decreased with the flow rate of dry air. It was also found that a maximum concentration was 20 mg/L and ozone capacity of 48 g/h with an input power of 1.4 kW. Moreover, in this generator, IP efficiency of 8.13 g/kWh was obtained at input power 0.45 kW and air flow rate of 9 L/min. Therefore, be the higher ozone capacity can be produced with higher input power; however, it provided lower IP efficiency. The effect of dry air flow rate and applied voltage on ozone concentrations have been studied. At last, spiral wire copper was very corrosive done to the interaction with ozone, and it is necessary to do a research for finding the best metals as an active electrode inside of the quartz dielectric. Copyright © 2017 BCREC GROUP. All rights reserved Received: 18th July 2016; Revised: 25th September 2016; Accepted: 5th October 2016 How to Cite: Nur, M., Susan, A.I., Muhlisin, Z., Arianto, F., Kinandana, A.W., Nurhasanah, I., Sumariyah, S., Wibawa, P.J., Gunawan, G., Usman, A. (2017. Evaluation of Novel Integrated Dielectric Barrier Discharge Plasma as Ozone Generator. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 24-31 (doi:10.9767/bcrec.12.1.605.24-31 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.605.24-31

  18. Second harmonic wave generation from a nonlinear combination of volume wave and overdense plasma in negative permeability space

    Science.gov (United States)

    Iwai, Akinori; Nakamura, Yoshihiro; Sakai, Osamu

    2016-09-01

    We clarify the relation between second harmonic wave (SH wave) and plasma generation in various experimental conditions by detecting properties of propagating electromagnetic waves (EM waves). Plasma has a nonlinear reaction against EM wave, generating harmonic waves which depends on electron density ne. In the case with increased ne, EM wave comes to be prevented from going into plasma with negative permittivity ɛp. Double-split-ring resonators (DSRRs), one of metamaterials, make permeability μD negative. We have shown that EM wave being volume wave can propagate into the combination of overdense plasma and DSRRs because of real negative value refractive index N. In our previous paper, we have confirmed enhanced SH wave (4.9 GHz) generation in the composite with 2.45-GHz input. In this report, we show the dependence of the SH wave emission with plasma generation on plasma parameters and gas conditions of plasma. Furthermore, we show the phase change with N variation of the composite space in the case with various input power as the proof of the negative index state.

  19. Models of high-Tc superconductivity and applications to electric generators and motors

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter

    We present the Ginzburg Landau model for mesoscopic high-Tc superconductors of complex geometry. It is shown that giant vortices can form at boundary defects. The relation between total magnetic flux penetration through the superconductor and the externally applied field is established. This is i....... This is in turn used in modelling high-Tc superconducting generators proposed for windmills in the project SuperWind (http://www.superwind.dk)....

  20. Analyzing the relationship between car generation and severity of motor-vehicle crashes in Denmark.

    Science.gov (United States)

    Rich, Jeppe; Prato, Carlo Giacomo; Hels, Tove; Lyckegaard, Allan; Kristensen, Niels Buus

    2013-05-01

    While the number of fatalities on Danish roads has decreased in the last 40 years, research has not investigated the contribution of legislation changes, enforcement measures, technological enhancements, infrastructural improvements and human factors to this reduction. In the context of a Danish car market with remarkably high registration tax that causes potential buyers to hold longer onto old cars, the relationship between technological enhancements of vehicles and severity of crashes requires particular attention. The current study investigated the relationship between car generation (i.e., car's first registration year) and injury severity sustained by car drivers involved in accidents in Denmark between 2004 and 2010. A generalized ordered logit model was estimated while controlling for several characteristics of the crash, the vehicle and the persons involved, and a sensitivity analysis was performed to assess the effect of car generation on drivers' injury severity. Results illustrate that newer car generations are associated to significantly lower probability of injury and fatality, and that replacing older cars with newer ones introduces significant and not to be overlooked benefits for both population and society.

  1. Differential in vitro inhibition of thrombin generation by anticoagulant drugs in plasma from patients with cirrhosis.

    Directory of Open Access Journals (Sweden)

    Wilma Potze

    Full Text Available BACKGROUND: Treatment and prevention of thrombotic complications is frequently required in patients with cirrhosis. However anticoagulant therapy is often withheld from these patients, because of the perceived bleeding diathesis. As a result of the limited clinical experience, the anticoagulant of choice for the various indications is still not known. OBJECTIVES: We evaluated the in vitro effect of clinically approved anticoagulant drugs in plasma from patients with cirrhosis. PATIENTS/METHODS: Thirty patients with cirrhosis and thirty healthy controls were studied. Thrombin generation assays were performed before and after addition of unfractionated heparin, low molecular weight heparin, fondaparinux, dabigatran, and rivaroxaban, to estimate anticoagulant potencies of these drugs. RESULTS: Addition of dabigatran led to a much more pronounced reduction in endogenous thrombin potential in patients compared to controls (72.6% reduction in patients vs. 12.8% reduction in controls, P<0.0001. The enhanced effect of dabigatran was proportional to the severity of disease. In contrast, only a slightly increased anticoagulant response to heparin and low molecular weight heparin and even a reduced response to fondaparinux and rivaroxaban was observed in plasma from cirrhotic patients as compared to control plasma. CONCLUSIONS: The anticoagulant potency of clinically approved drugs differs substantially between patients with cirrhosis and healthy individuals. Whereas dabigatran and, to a lesser extent, heparin and low molecular weight heparin are more potent in plasma from patients with cirrhosis, fondaparinux and rivaroxaban showed a decreased anticoagulant effect. These results may imply that in addition to dose adjustments based on altered pharmacokinetics, drug-specific dose adjustments based on altered anticoagulant potency may be required in patients with cirrhosis.

  2. Phonon spectral functions of photo-generated hot carrier plasmas: effects of carrier screening and plasmon-phonon coupling

    Science.gov (United States)

    Yi, Kyung-Soo; Kim, Hye-Jung

    2017-02-01

    We investigate spectral behavior of phonon spectral functions in an interacting multi-component hot carrier plasma. Spectral analysis of various phonon spectral functions is performed considering carrier-phonon channels of polar and nonpolar optical phonons, acoustic deformation-potential, and piezoelectric Coulomb couplings. Effects of phonon self-energy corrections are examined at finite temperature within a random phase approximation extended to include the effects of dynamic screening, plasmon-phonon coupling, and local-field corrections of the plasma species. We provide numerical data for the case of a photo-generated electron-hole plasma formed in a wurtzite GaN. Our result shows the clear significance of the multiplicity of the plasma species in the phonon spectral functions of a multi-component plasma giving rise to a variety of spectral behaviors of carrier-phonon coupled collective modes. A useful sum rule on the plasma-species-resolved dielectric functions is also found.

  3. Ion acceleration enhancement in laser-generated plasmas by metallic doped hydrogenated polymers

    Directory of Open Access Journals (Sweden)

    Angela Maria Mezzasalma

    2009-05-01

    Full Text Available Laser-generated plasmas in vacuum were obtained by ablating hydrogenated polymers at the Physics Department of the University of Messina and at the PALS Laboratory in Prague. In the first case a 3 ns,532 nm Nd:Yag laser, at 1010 W/cm2 intensity was employed.In the second case a 300 ps, 438 nm iodine laser, at 5x1014W/cm2 intensity was employed. Different ion collectors were usedin a time-of-flight configuration to monitor the ejected ions from theplasma at different angles with respect to the direction normal tothe target surface. Measurements demonstrated that the mean ionvelocity, directed orthogonally to the target surface, increases forablation of polymers doped with metallic elements with respect tothe nondoped one. The possible mechanism explaining theresults can be found in the different electron density of theplasma, due to the higher number of electrons coming from the dopingelements. This charge enhancement increases the equivalent ionvoltage acceleration, i.e. the electric field generated in the non-equilibrium plasma placed in front of the ablated target surface.

  4. High duty factor Plasma Generator for CERN’s Superconducting Proton Linac

    CERN Document Server

    Lettry, J; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, JM; Kuchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-01-01

    CERN’s Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN’s PS-Booster. Its ion source is a non-cesiated RF driven H- volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H- during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the LHC, it consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV Synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H- during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H- plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the...

  5. Brilliant petawatt gamma-ray pulse generation in quantum electrodynamic laser-plasma interaction

    Science.gov (United States)

    Chang, H. X.; Qiao, B.; Huang, T. W.; Xu, Z.; Zhou, C. T.; Gu, Y. Q.; Yan, X. Q.; Zepf, M.; He, X. T.

    2017-03-01

    We show a new resonance acceleration scheme for generating ultradense relativistic electron bunches in helical motions and hence emitting brilliant vortical γ-ray pulses in the quantum electrodynamic (QED) regime of circularly-polarized (CP) laser-plasma interactions. Here the combined effects of the radiation reaction recoil force and the self-generated magnetic fields result in not only trapping of a great amount of electrons in laser-produced plasma channel, but also significant broadening of the resonance bandwidth between laser frequency and that of electron betatron oscillation in the channel, which eventually leads to formation of the ultradense electron bunch under resonant helical motion in CP laser fields. Three-dimensional PIC simulations show that a brilliant γ-ray pulse with unprecedented power of 6.7 PW and peak brightness of 1025 photons/s/mm2/mrad2/0.1% BW (at 15 MeV) is emitted at laser intensity of 1.9 × 1023 W/cm2.

  6. Effects of permanent magnet arrangements and antenna locations on the generation of multicusp electron cyclotron resonance plasma

    Energy Technology Data Exchange (ETDEWEB)

    Namura, T. (Kyoto Research Laboratory, Matsushita Electronics Corporation, Kyoto 601 (Japan)); Arikata, I. (Himeji Institute of Technology, Syosha, Himeji 671-22 (Japan)); Fukumasa, O. (Department of Electrical Engineering, Yamaguchi University, Ube 755 (Japan)); Kubo, M.; Itatani, R. (Department of Electronics, Kyoto University, Kyoto 606 (Japan))

    1992-01-01

    A comparative study on the generation of 2.45-GHz multicusp electron cyclotron resonance (ECR) plasma is performed. Looped cusp structures such as the ring-cusp give a low-power and low-pressure ignition, and vice versa, indicating an importance to keep the electron trajetory of gradient-{ital B} drift motion inside the chamber even in the case of ECR plasmas. The importance of the antenna location in such multicusp fields is elucidated by comparison in two cases of the axial antenna located in the weak magnetic field region, generating a hydrogen plasma of limited density ({ital n}{sub {ital e}}{lt}7.4{times}10{sup 10} cm{sup {minus}3}), and a radial antenna located in the strong magnetic field region, generating an overdense plasma ({ital n}{sub {ital e}}{similar to}2{times}10{sup 11} cm{sup {minus}3}).

  7. Generation and analysis of plasmas with centrally reduced helicity in full-tungsten ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bock, Alexander

    2016-03-01

    The most promising concepts for harnessing nuclear fusion are toroidal devices like tokamaks, where a plasma is confined by helically twisted magnetic field lines. To provide the twisting of the field lines, a tokamak relies on a toroidal current in the plasma, which is largely generated by a transformer. As such, conventional tokamaks are limited to pulsed operation. Moreover, this current makes tokamak plasmas prone to numerous confinement degrading magnetohydrodynamic (MHD) instabilities that can emerge at locations where the field line helicity q takes on rational values like 1/1, 3/2 or 2/1, i.e. sawteeth or neoclassical tearing modes (NTMs). This thesis presents studies of plasmas with centrally elevated q-profiles created by external electron-cyclotron and neutral beam current drive (ECCD/NBCD) under steady-state conditions in the full-tungsten tokamak ASDEX Upgrade. Without the usually monotonic q-profile, instabilities of low helicity disappear, thereby improving the plasma stability. Furthermore, elevating q increases the amount of so-called (toroidal) bootstrap current, which the plasma drives by itself in the presence of pressure gradients, thereby reducing the reliance on the transformer. In the best case, an advanced tokamak (AT) could thus run in steady state. Additionally, an elevated and thus flat/slightly reversed q-profile is thought to improve confinement by impeding turbulent transport. Reconstruction of the tailored q-profile is accomplished with the new integrated data equilibrium (IDE) code and information from a key diagnostic that is based on the Motional Stark Effect (MSE). During the course of this work it was discovered that the MSE diagnostic suffers from interference from polarised background light. A prototype mitigation system was successfully tested. Also, non-linearities in the diagnostic's optical relay system were found and a calibration scheme devised to take them into account. Both the conventional approach of AT

  8. Stable droplet generator for a high brightness laser produced plasma extreme ultraviolet source

    Science.gov (United States)

    Vinokhodov, A.; Krivokorytov, M.; Sidelnikov, Yu.; Krivtsun, V.; Medvedev, V.; Bushuev, V.; Koshelev, K.; Glushkov, D.; Ellwi, S.

    2016-10-01

    We present the results of the low-melting liquid metal droplets generation based on excited Rayleigh jet breakup. We discuss on the operation of the industrial and in-house designed and manufactured dispensing devices for the droplets generation. Droplet diameter can be varied in the range of 30-90 μm. The working frequency of the droplets, velocity, and the operating temperature were in the ranges of 20-150 kHz, 4-15 m/s, and up to 250 °C, respectively. The standard deviations for the droplet center of mass position both their diameter σ < 1 μm at the distance of 45 mm from the nozzle. Stable operation in the long-term (over 1.5 h) was demonstrated for a wide range of the droplet parameters: diameters, frequencies, and velocities. Physical factors affecting the stability of the generator operation have been identified. The technique for droplet synchronization, allowing using the droplet as a target for laser produced plasma, has been created; in particular, the generator has been successfully used in a high brightness extreme ultraviolet (EUV) light source. The operation with frequency up to 8 kHz was demonstrated as a result of the experimental simulation, which can provide an average brightness of the EUV source up to ˜1.2 kW/mm2 sr.

  9. Formation and characterization of the vortices generated by a DBD plasma actuator in burst mode

    Science.gov (United States)

    Mishra, Bal Krishan; Panigrahi, P. K.

    2017-02-01

    The present study reports the formation and evolution characteristics of the continuously generated vortical structure and resulting flow field in quiescent air induced by a dielectric-barrier-discharge (DBD) plasma actuator in burst mode operation. A starting vortex is formed during the initial actuation period, which disappears after a small time interval for continuous mode operation of the DBD plasma actuator. A burst input signal to the actuator generates a train of self-similar vortices. The behaviour of vortices and the average flow field induced by the actuator has been studied using high speed schlieren visualization and particle image velocimetry technique for different actuation amplitude and duty cycle parameters. These repeating vortices travel faster than the starting vortex, and the vortex core velocity of these repeating vortices increases with increase in duty cycle parameter. Fuller u-velocity profile, higher v-velocity near the edge of the outer shear layer region, and higher growth of the wall jet thickness is observed due to enhanced entrainment by repeating vortices for burst mode operation. The repeating vortices travel at an angle of 21° relative to the wall surface for duty cycle parameter of 90.9% in comparison to 31° for the starting vortex. Self-similarity of the velocity profile is delayed in the streamwise direction for burst mode operation in comparison to that for the continuous mode of operation. This can be attributed to delay in attaining the maximum velocity of the wall jet profile and presence of coherent structures for the burst mode operation. The non-dimensional vortex core location and size for repeating vortices follow power law fit similar to the starting vortex with difference in value of the power law exponent. The phase difference between the input voltage and current drawn is in the range of π/12 to π/9 (in radians) for both continuous and burst mode operation indicating identical electrical behaviour of the

  10. Structured plasma waveguides and deep EUV generation enabled by intense laser-cluster interactions

    Science.gov (United States)

    Layer, Brian David

    Using the unique properties of the interaction between intense, short-pulse lasers and nanometer scale van-der-Waals bonded aggregates (or 'clusters'), modulated waveguides in hydrogen, argon and nitrogen plasmas were produced and extreme ultraviolet (EUV) light was generated in deeply ionized nitrogen plasmas. A jet of clusters behaves as an array of mass-limited, solid-density targets with the average density of a gas. Two highly versatile experimental techniques are demonstrated for making preformed plasma waveguides with periodic structure within a laser-ionized cluster jet. The propagation of ultra-intense femtosecond laser pulses with intensities up to 2 x1017 W/cm2 has been experimentally demonstrated in waveguides generated using both methods, limited by available laser energy. The first uses a 'ring grating' to impose radial intensity modulations on the channel-generating laser pulse, which leads to axial intensity modulations at the laser focus within the cluster jet target. This creates a waveguide with axial modulations in diameter with a period between 35 mum and 2 mm, determined by the choice of ring grating. The second method creates modulated waveguides by focusing a uniform laser pulse within a jet of clusters with ow that has been modulated by periodically spaced wire obstructions. These wires make sharp, stable voids as short as 50 mum with a period as small as 200 mum within waveguides of hydrogen, nitrogen, and argon plasma. The gaps persist as the plasma expands for the full lifetime of the waveguide. This technique is useful for quasi-phase matching applications where index-modulated guides are superior to diameter modulated guides. Simulations show that these 'slow wave' guiding structures could allow direct laser acceleration of electrons, achieving gradients of 80 MV/cm and 10 MV/cm for laser pulse powers of 1.9 TW and 30 GW, respectively. Results are also presented from experiments in which a nitrogen cluster jet from a cryogenically

  11. Transverse Dynamics and Energy Tuning of Fast Electrons Generated in Sub-Relativistic Intensity Laser Pulse Interaction with Plasmas

    CERN Document Server

    Mori, M; Daito, I; Kotaki, H; Hayashi, Y; Yamazaki, A; Ogura, K; Sagisaka, A; Koga, J; Nakajima, K; Daido, H; Bulanov, S V; Kimura, T

    2006-01-01

    The regimes of quasi-mono-energetic electron beam generation were experimentally studied in the sub-relativistic intensity laser plasma interaction. The observed electron acceleration regime is unfolded with two-dimensional-particle-in-cell simulations of laser-wakefield generation in the self-modulation regime.

  12. Chemical erosion of carbon at ITER relevant plasma fluxes: Results from the linear plasma generator Pilot-PSI

    NARCIS (Netherlands)

    van Rooij, G. J.; Westerhout, J.; Brezinsek, S.; Rapp, J.

    2011-01-01

    The chemical erosion of carbon was investigated in the linear plasma device Pilot-PSI for ITER divertor relevant hydrogen plasma flux densities 10(23) < Gamma < 10(25) m(-2) s(-1). The erosion was analyzed in situ by optical emission spectroscopy and post mortem by surface profilometry. The ex

  13. Magnetic field generation, Weibel-mediated collisionless shocks, and magnetic reconnection in colliding laser-produced plasmas

    Science.gov (United States)

    Fox, W.; Bhattacharjee, A.; Fiksel, G.

    2016-10-01

    Colliding plasmas are ubiquitous in astrophysical environments and allow conversion of kinetic energy into heat and, most importantly, the acceleration of particles to extremely high energies to form the cosmic ray spectrum. In collisionless astrophysical plasmas, kinetic plasma processes govern the interaction and particle acceleration processes, including shock formation, self-generation of magnetic fields by kinetic plasma instabilities, and magnetic field compression and reconnection. How each of these contribute to the observed spectra of cosmic rays is not fully understood, in particular both shock acceleration processes and magnetic reconnection have been proposed. We will review recent results of laboratory astrophysics experiments conducted at high-power, inertial-fusion-class laser facilities, which have uncovered significant results relevant to these processes. Recent experiments have now observed the long-sought Weibel instability between two interpenetrating high temperature plasma plumes, which has been proposed to generate the magnetic field necessary for shock formation in unmagnetized regimes. Secondly, magnetic reconnection has been studied in systems of colliding plasmas using either self-generated magnetic fields or externally applied magnetic fields, and show extremely fast reconnection rates, indicating fast destruction of magnetic energy and further possibilities to accelerate particles. Finally, we highlight kinetic plasma simulations, which have proven to be essential tools in the design and interpretation of these experiments.

  14. New approaches for the reduction of plasma arc drop in second-generation thermionic converters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hatziprokopiou, M.E.; Shaw, D.T.

    1981-03-31

    Investigations of ion generation and recombination mechanisms in the cesium plasma as they pertain to the advanced mode thermionic energy converter are described. The changes in plasma density and temperature within the converter have been studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation have been investigated in some detail, namely vibrationally excited N/sub 2/ as an energy source of ionization of Cs ions in a DC discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N/sub 2/-Cs mixture. The experimental data obtained and discussed show that all three techniques - i.e. the non-LTE high-voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power - have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

  15. Effects of assisted magnetic field to an atmospheric-pressure plasma jet on radical generation at the plasma-surface interface and bactericidal function

    Science.gov (United States)

    Liu, Chih-Tung; Kumakura, Takumi; Ishikawa, Kenji; Hashizume, Hiroshi; Takeda, Keigo; Ito, Masafumi; Hori, Masaru; Wu, Jong-Shinn

    2016-12-01

    A configuration of magnetic-assisted-plasma (MAP) on helium-based atmospheric-pressure plasma jet (APPJ) with an axial magnetic-field of 0.587 T is proposed, which provides good ability for killing bacteria Escherichia coli on the agar surface. Optically, we confirmed that the MAP increased approximately 2.4 times in the electron density estimated by the Stark broadening of H β line emission, and approximately 1.5 times enhancement of atomic oxygen concentration measured by vacuum ultraviolet absorption spectroscopy (VUVAS). Moreover, the generation of hydroxyl radical in the water increased 1.5 times, confirmed by the spin-trapping electron spin-resonance technique. In addition, the bactericidal experiments demonstrated 2.4 times higher for E. coli by the MAP treatment. The MAP configuration is proposed to be highly useful for future bio-medical applications by enhancing the radical generation at the plasma/substrate interface region.

  16. Oblique Bernstein Mode Generation Near the Upper-hybrid Frequency in Solar Pre-flare Plasmas

    Science.gov (United States)

    Kryshtal, A.; Fedun, V.; Gerasimenko, S.; Voitsekhovska, A.

    2015-11-01

    We study analytically the generation process of the first harmonics of the pure electron weakly oblique Bernstein modes. This mode can appear as a result of the rise and development of a corresponding instability in a solar active region. We assume that this wave mode is modified by the influence of pair Coulomb collisions and a weak large-scale sub-Dreicer electric field in the pre-flare chromosphere near the footpoints of a flare loop. To describe the pre-flare plasma we used the model of the solar atmosphere developed by Fontenla, Avrett, and Loeser ( Astrophys. J. 406, 319, 1993). We show that the generated first harmonic is close to the upper-hybrid frequency. This generation process begins at the very low threshold values of the sub-Dreicer electric field and well before the beginning of the preheating phase of a flare. We investigate the necessary conditions for the existence of non-damped first harmonics of oblique Bernstein waves with small amplitudes in the flare area.

  17. Software architecture for control and data acquisition of linear plasma generator Magnum-PSI

    Energy Technology Data Exchange (ETDEWEB)

    Groen, P.W.C., E-mail: p.w.c.groen@differ.nl [FOM Institute DIFFER – Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE, Nieuwegein (Netherlands); Beveren, V. van; Broekema, A.; Busch, P.J.; Genuit, J.W.; Kaas, G.; Poelman, A.J.; Scholten, J.; Zeijlmans van Emmichoven, P.A. [FOM Institute DIFFER – Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE, Nieuwegein (Netherlands)

    2013-10-15

    Highlights: ► An architecture based on a modular design. ► The design offers flexibility and extendability. ► The design covers the overall software architecture. ► It also covers its (sub)systems’ internal structure. -- Abstract: The FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research has completed the construction phase of Magnum-PSI, a magnetized, steady-state, large area, high-flux linear plasma beam generator to study plasma surface interactions under ITER divertor conditions. Magnum-PSI consists of several hardware subsystems, and a variety of diagnostic systems. The COntrol, Data Acquisition and Communication (CODAC) system integrates these subsystems and provides a complete interface for the Magnum-PSI users. Integrating it all, from the lowest hardware level of sensors and actuators, via the level of networked PLCs and computer systems, up to functions and classes in programming languages, demands a sound and modular software architecture, which is extendable and scalable for future changes. This paper describes this architecture, and the modular design of the software subsystems. The design is implemented in the CODAC system at the level of services and subsystems (the overall software architecture), as well as internally in the software subsystems.

  18. Plasmoid ejection and secondary current sheet generation from magnetic reconnection in laser-plasma interaction.

    Science.gov (United States)

    Dong, Quan-Li; Wang, Shou-Jun; Lu, Quan-Ming; Huang, Can; Yuan, Da-Wei; Liu, Xun; Lin, Xiao-Xuan; Li, Yu-Tong; Wei, Hui-Gang; Zhong, Jia-Yong; Shi, Jian-Rong; Jiang, Shao-En; Ding, Yong-Kun; Jiang, Bo-Bin; Du, Kai; He, Xian-Tu; Yu, M Y; Liu, C S; Wang, Shui; Tang, Yong-Jian; Zhu, Jian-Qiang; Zhao, Gang; Sheng, Zheng-Ming; Zhang, Jie

    2012-05-25

    Reconnection of the self-generated magnetic fields in laser-plasma interaction was first investigated experimentally by Nilson et al. [Phys. Rev. Lett. 97, 255001 (2006)] by shining two laser pulses a distance apart on a solid target layer. An elongated current sheet (CS) was observed in the plasma between the two laser spots. In order to more closely model magnetotail reconnection, here two side-by-side thin target layers, instead of a single one, are used. It is found that at one end of the elongated CS a fanlike electron outflow region including three well-collimated electron jets appears. The (>1 MeV) tail of the jet energy distribution exhibits a power-law scaling. The enhanced electron acceleration is attributed to the intense inductive electric field in the narrow electron dominated reconnection region, as well as additional acceleration as they are trapped inside the rapidly moving plasmoid formed in and ejected from the CS. The ejection also induces a secondary CS.

  19. Effects of CSR Generated from Upstream Bends in a Laser Plasma Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, C.; Qiang, J.; Venturini, M.

    2013-08-28

    The recent proposal [1] of a Laser Plasma Storage Ring (LPSR) envisions the use of a laser-plasma (LP) acceleration module to inject an electron beam into a compact 500 MeV storage ring. Electron bunches generated by LP methods are naturally very short (tens of femtoseconds), presenting peak currents on the order of 10 kA or higher. Of obvious concern is the impact of collective effects and in particular Coherent Synchrotron Radiation (CSR) on the beam dynamics in the storage ring. Available simulation codes (e.g. Elegant [2]) usually include transient CSR effects but neglect the contribution of radiation emitted from trailing magnets. In a compact storage ring, with dipole magnets close to each other, cross talking between different magnets could in principle be important.In this note we investigate this effect for the proposed LPSR and show that, in fact, this effect is relatively small. However our analysis also indicates that CSR effects in general would be quite strong and deserve a a careful study.

  20. Effects of CSR Generated from Upstream Bends in a Laser Plasma Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, C.; Qiang, J.; Venturini, M.

    2013-08-28

    The recent proposal [1] of a Laser Plasma Storage Ring (LPSR) envisions the use of a laser-plasma (LP) acceleration module to inject an electron beam into a compact 500 MeV storage ring. Electron bunches generated by LP methods are naturally very short (tens of femtoseconds), presenting peak currents on the order of 10 kA or higher. Of obvious concern is the impact of collective effects and in particular Coherent Synchrotron Radiation (CSR) on the beam dynamics in the storage ring. Available simulation codes (e.g. Elegant [2]) usually include transient CSR effects but neglect the contribution of radiation emitted from trailing magnets. In a compact storage ring, with dipole magnets close to each other, cross talking between different magnets could in principle be important.In this note we investigate this effect for the proposed LPSR and show that, in fact, this effect is relatively small. However our analysis also indicates that CSR effects in general would be quite strong and deserve a a careful study.

  1. D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

    Science.gov (United States)

    Torrisi, L.; Cutroneo, M.; Cavallaro, S.; Ullschmied, J.

    2015-06-01

    Deuterium-Deuterium fusion processes were generated by focusing the 3 TW PALS Laser on solid deuterated polyethylene targets placed in vacuum. Deuterium ion acceleration of the order of 4 MeV was obtained using laser irradiance Iλ2 ˜ 5 × 1016 W μm2/cm2 on the target. Thin and thick targets, at low and high density, were irradiated and plasma properties were monitored "on line" and "off line". The ion emission from plasma was monitored with Thomson Parabola Spectrometer, track detectors and ion collectors. Fast semiconductor detectors based on SiC and fast plastic scintillators, both employed in time-of-flight configuration, have permitted to detect the characteristic 3.0 MeV protons and 2.45 MeV neutrons emission from the nuclear fusion reactions. From massive absorbent targets we have evaluated the neutron flux by varying from negligible values up to about 5 × 107 neutrons per laser shot in the case of foams targets, indicating a reaction rate of the order of 108 fusion events per laser shot using "advanced targets".

  2. Generation of uniform atmospheric pressure argon glow plasma by dielectric barrier discharge

    Indian Academy of Sciences (India)

    Raju Bhai Tyata; Deepak Prasad Subedi; Rajendra Shrestha; Chiow San Wong

    2013-03-01

    In this paper, atmospheric pressure glow discharges (APGD) in argon generated in parallel plate dielectric barrier discharge system is investigated by means of electrical and optical measurements. Using a high voltage (0–20 kV) power supply operating at 10–30 kHz, homogeneous and steady APGD has been observed between the electrodes with gap spacing from 0.5 mm to 2 mm and with a dielectric barrier of thickness 2 mm while argon gas is fed at a controlled flow rate of 11/min. The electron temperature and electron density of the plasma are determined by means of optical emission spectroscopy. Our results show that the electron density of the discharge obtained is of the order of 1016 cm-3 while the electron temperature is estimated to be 0.65 eV. The important result is that electron density determined from the line intensity ratio method and stark broadening method are in very good agreement. The Lissajous figure is used to estimate the energy deposited to the glow discharge. It is found that the energy deposited to the discharge is in the range of 20 to 25 $\\$J with a discharge voltage of 1.85 kV. The energy deposited to the discharge is observed to be higher at smaller gas spacing. The glow discharge plasma is tested to be effective in reducing the hydrophobicity of polyethylene film significantly.

  3. D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

    Directory of Open Access Journals (Sweden)

    Torrisi L.

    2015-01-01

    Full Text Available Deuterium-Deuterium fusion processes were generated by focusing the 3 TW PALS Laser on solid deuterated polyethylene targets placed in vacuum. Deuterium ion acceleration of the order of 4 MeV was obtained using laser irradiance Iλ2 ∼ 5 × 1016 W μm2/cm2 on the target. Thin and thick targets, at low and high density, were irradiated and plasma properties were monitored “on line” and “off line”. The ion emission from plasma was monitored with Thomson Parabola Spectrometer, track detectors and ion collectors. Fast semiconductor detectors based on SiC and fast plastic scintillators, both employed in time-of-flight configuration, have permitted to detect the characteristic 3.0 MeV protons and 2.45 MeV neutrons emission from the nuclear fusion reactions. From massive absorbent targets we have evaluated the neutron flux by varying from negligible values up to about 5 × 107 neutrons per laser shot in the case of foams targets, indicating a reaction rate of the order of 108 fusion events per laser shot using “advanced targets”.

  4. Synthesis and Sintering of Mg2Si Thermoelectric Generator by Spark Plasma Sintering

    Institute of Scientific and Technical Information of China (English)

    YANG Meijun; ZHANG Lianmeng; SHEN Qiang

    2008-01-01

    Raw Mg,Si powder were used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering (SPS).The optimum parameters to synthesize pure Mg2Si powder were found to be 823 K,0 MPa,10 min with excessive content of 10wt% Mg from the stoichiometric Mg2Si.Mg2Si bulk was synthesized and densified simultaneously at low temperature (823 K) and high pressure (higher than 100 MPa) from the raw powder,but Mg,Si could not react completely,and the sample was not very dense with some microcracks on the surface.Then,Mg,Si powder reacted at 823 K,0 MPa,10 min in SPS chamber to form Mg2Si green compact,again sintered by SPS at 1023 K,20 MPa,5 min.The fabricated sample only contained MgESi phase with fully relative density.

  5. Further investigations on the Neutron Flux Generation in a Plasma Discharge Electrolytic Cell

    CERN Document Server

    Faccini, R; Polosa, A D; Angelone, M; Castagna, E; Lecci, S; Loreti, S; Pietropaolo, A; Pillon, M; Sansovini, M; Sarto, F; Violante, V; Bedogni, R; Esposito, A

    2014-01-01

    Our recent paper on the "Search for Neutron Flux Generation in a Plasma Discharge Electrolytic Cell" [1] has as main goal the validation of the experiment in Ref.[2]. As a follow-up, Ref.[3] moves a set of objections on our procedure and presents argumentations on why the experiments should not yield the same results. We collect here additional material and calculations that contribute to understanding the observed discrepancies. Furthermore we prove that the absence of signals from Indium activation detectors reported also for the experiment of Ref.[2] is a clear indication that neutron production does not occur. [1] R.Faccini et al arXiv:1310.4749 [2] D.Cirillo et al, Key Engineering Materials 495, 104 (2012). [3] A.Widom et al. arXiv:1311.2447

  6. Athermal Annealing of Semiconductors Using Shock Waves Generated by a Laser-Plasma

    Science.gov (United States)

    Fischer, R. P.; Grun, J.; Mignogna, R.; Donnelly, D. W.; Covington, B.

    2004-07-01

    We are investigating an annealing technique in which shock or sound waves generated by a laser-plasma are used to anneal a semiconductor. The athermal annealing (AA) process occurs very rapidly, which results in almost no diffusion of. dopants. A HeNe laser is used to measure the reflectivity of the silicon as a function of time. Measurements show that the annealing occurs in 1.8 μsec, which is the acoustic time scale for waves to propagate from the focus through the AA region. A knife-edge technique is employed to study acoustic waves in the sample by measuring the deflection of the probe beam. Initial results for aluminum samples irradiated at modest laser intensities (200 mJ, 50 nsec) show well-defined surface acoustic waves. However, both silicon and GaAs have more complicated structure which resemble Lamb (plate) waves.

  7. Electron Thermal Capacity in Plasma Generated at Cavitation Bubble Collapse in D-acetone

    CERN Document Server

    Kostenko, B F

    2004-01-01

    The latest experimental data on nuclear reaction product registration at cavitation bubble collapse in deuterated acetone (C$_3$D$_6$O) still argue in favour of existence of a new possibility to realize the thermonuclear synthesis. Theoretical description based on numerical solution of simultaneous conservation equations for gaseous and liquid phases also confirms this possibility, although it requires further more precise definitions. In particular, description of electron degrees of freedom in very dense nonequilibrium plasma generated at the final stage of bubble collapse needs specification. In the present paper, calculations of electron thermal capacity in the deuterated acetone multiple ionization region at electron temperatures $T_e \\simeq 10^4 $ K and above and compression range $\\rho/\\rho_0 \\simeq 1 \\div 100$ have been fulfilled on the basis of direct numerical solution of equation for chemical potential.

  8. Upgrade of the IGN-14 neutron generator for research on detection of fusion-plasma products

    Energy Technology Data Exchange (ETDEWEB)

    Igielski, Andrzej; Kurowski, Arkadiusz; Janik, Władysław; Gabańska, Barbara; Woźnicka, Urszula, E-mail: Urszula.Woznicka@ifj.edu.pl

    2015-10-11

    The fast neutron generator (IGN-14) at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Kraków (Poland) is a laboratory multi-purpose experimental device. Neutrons are produced in a beam-target D–D or D–T reactions. A new vacuum chamber installed directly to the end of the ion guide of IGN-14 makes it possible to measure not only neutrons but also alpha particles in the presence of a mixed radiation field of other accompanying reaction products. The new experimental setup allows test detectors dedicated to spectrometric measurements of thermonuclear fusion reaction products. - Highlights: • Nuclear reactions at the target correspond to the fusion reaction in hot plasma. • Measuring vacuum chamber has been built and installed. • Spatial distribution of the particle mixed fields in chamber was calculated. • New experimental setup for tests of detectors dedicated to measure of fusion reaction products.

  9. Predictions for the energy loss of light ions in laser-generated plasmas at low and medium velocities.

    Science.gov (United States)

    Cayzac, W; Bagnoud, V; Basko, M M; Blažević, A; Frank, A; Gericke, D O; Hallo, L; Malka, G; Ortner, A; Tauschwitz, An; Vorberger, J; Roth, M

    2015-11-01

    The energy loss of light ions in dense plasmas is investigated with special focus on low to medium projectile energies, i.e., at velocities where the maximum of the stopping power occurs. In this region, exceptionally large theoretical uncertainties remain and no conclusive experimental data are available. We perform simulations of beam-plasma configurations well suited for an experimental test of ion energy loss in highly ionized, laser-generated carbon plasmas. The plasma parameters are extracted from two-dimensional hydrodynamic simulations, and a Monte Carlo calculation of the charge-state distribution of the projectile ion beam determines the dynamics of the ion charge state over the whole plasma profile. We show that the discrepancies in the energy loss predicted by different theoretical models are as high as 20-30%, making these theories well distinguishable in suitable experiments.

  10. Control of Reactive Species Generated by Low-frequency Biased Nanosecond Pulse Discharge in Atmospheric Pressure Plasma Effluent

    Science.gov (United States)

    Takashima, Keisuke; Kaneko, Toshiro

    2016-09-01

    The control of hydroxyl radical and the other gas phase species generation in the ejected gas through air plasma (air plasma effluent) has been experimentally studied, which is a key to extend the range of plasma treatment. Nanosecond pulse discharge is known to produce high reduced electric field (E/N) discharge that leads to efficient generation of the reactive species than conventional low frequency discharge, while the charge-voltage cycle in the low frequency discharge is known to be well-controlled. In this study, the nanosecond pulse discharge biased with AC low frequency high voltage is used to take advantages of these discharges, which allows us to modulate the reactive species composition in the air plasma effluent. The utilization of the gas-liquid interface and the liquid phase chemical reactions between the modulated long-lived reactive species delivered from the air plasma effluent could realize efficient liquid phase chemical reactions leading to short-lived reactive species production far from the air plasma, which is crucial for some plasma agricultural applications.

  11. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    Science.gov (United States)

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800 mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10) s(-1) cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9) s(-1) cm(-2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300 mA, 45 kV deuteron beam directed to D2O target demonstrated 10(9) s(-1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source.

  12. High-order harmonic generation in a plasma plume of in situ laser-produced silver nanoparticles

    Science.gov (United States)

    Singhal, H.; Ganeev, R. A.; Naik, P. A.; Chakera, J. A.; Chakravarty, U.; Vora, H. S.; Srivastava, A. K.; Mukherjee, C.; Navathe, C. P.; Deb, S. K.; Gupta, P. D.

    2010-10-01

    The results of the experimental study of high-order harmonic generation (HHG) from the interaction of 45-fs Ti:sapphire laser pulses with plasma plumes of Ag nanoparticles produced in situ are presented in this article. The nanoparticles were generated by the interaction of 300-ps, 20-mJ laser pulses with bulk silver targets at an intensity of ~1×1013W/cm2. The spectral characteristics of the HHG from nanoparticles produced in situ are compared with the HHG from monoparticle plasma plumes and with the HHG from preformed nanoparticle-containing plasma plumes. The cutoff harmonic order generated using the in situ silver nanoparticles is at the 21st harmonic order.

  13. Analysis of the Comprehensive Physical Field for a New Flywheel Energy Storage Motor/Generator on Ships

    Institute of Scientific and Technical Information of China (English)

    Yali Yu; Yuanxi Wang; Guosheng Zhang; Feng Sun

    2012-01-01

    A novel flywheel energy storage (FES) motor/generator (M/G) was proposed for marine systems.The purpose was to improve the power quality of a marine power system (MPS) and strengthen the energy recycle.Two structures including the magnetic or non-magnetic inner-rotor were contrasted in the magnetostatic field by using finite element analysis (FEA).By optimally designing the size parameters,the average speed of FEA results of was 17 200 r/m,and the current was controlled between 62 and 68 A in the transient field.The electrical machine electromagnetism design was further optimized by the FEA in the temperature field,to find the local overheating point under the normal operation condition and provide guidance for the cooling system.Finally,it can be concluded from the comprehensive physical field analysis that the novel redundant structure M/G can improve the efficiency of the M/G and maintain the stability of the MPS.

  14. Examining the contribution of motor movement and language dominance to increased left lateralization during sign generation in native signers.

    Science.gov (United States)

    Gutierrez-Sigut, Eva; Payne, Heather; MacSweeney, Mairéad

    2016-08-01

    The neural systems supporting speech and sign processing are very similar, although not identical. In a previous fTCD study of hearing native signers (Gutierrez-Sigut, Daws, et al., 2015) we found stronger left lateralization for sign than speech. Given that this increased lateralization could not be explained by hand movement alone, the contribution of motor movement versus 'linguistic' processes to the strength of hemispheric lateralization during sign production remains unclear. Here we directly contrast lateralization strength of covert versus overt signing during phonological and semantic fluency tasks. To address the possibility that hearing native signers' elevated lateralization indices (LIs) were due to performing a task in their less dominant language, here we test deaf native signers, whose dominant language is British Sign Language (BSL). Signers were more strongly left lateralized for overt than covert sign generation. However, the strength of lateralization was not correlated with the amount of time producing movements of the right hand. Comparisons with previous data from hearing native English speakers suggest stronger laterality indices for sign than speech in both covert and overt tasks. This increased left lateralization may be driven by specific properties of sign production such as the increased use of self-monitoring mechanisms or the nature of phonological encoding of signs.

  15. A novel approach to locomotion learning: Actor-Critic architecture using central pattern generators and dynamic motor primitives.

    Science.gov (United States)

    Li, Cai; Lowe, Robert; Ziemke, Tom

    2014-01-01

    In this article, we propose an architecture of a bio-inspired controller that addresses the problem of learning different locomotion gaits for different robot morphologies. The modeling objective is split into two: baseline motion modeling and dynamics adaptation. Baseline motion modeling aims to achieve fundamental functions of a certain type of locomotion and dynamics adaptation provides a "reshaping" function for adapting the baseline motion to desired motion. Based on this assumption, a three-layer architecture is developed using central pattern generators (CPGs, a bio-inspired locomotor center for the baseline motion) and dynamic motor primitives (DMPs, a model with universal "reshaping" functions). In this article, we use this architecture with the actor-critic algorithms for finding a good "reshaping" function. In order to demonstrate the learning power of the actor-critic based architecture, we tested it on two experiments: (1) learning to crawl on a humanoid and, (2) learning to gallop on a puppy robot. Two types of actor-critic algorithms (policy search and policy gradient) are compared in order to evaluate the advantages and disadvantages of different actor-critic based learning algorithms for different morphologies. Finally, based on the analysis of the experimental results, a generic view/architecture for locomotion learning is discussed in the conclusion.

  16. A Novel Approach to Locomotion Learning: Actor-Critic Architecture using Central Pattern Generators and Dynamic Motor Primitives

    Directory of Open Access Journals (Sweden)

    Cai eLi

    2014-10-01

    Full Text Available In this article, we propose an architecture of a bio-inspired controller that addresses the problem of learning different locomotion gaits for different robot morphologies. The modelling objective is split into two: baseline motion modelling and dynamics adaptation. Baseline motion modelling aims to achieve fundamental functions of a certain type of locomotion and dynamics adaptation provides a ``reshaping function for adapting the baseline motion to desired motion. Based on this assumption, a three-layer architecture is developed using central pattern generators (CPGs, a bio-inspired locomotor center for the the baseline motion and dynamic motor primitives (DMPs, a model with universal ``reshaping functions. In this article, we use this architecture with the actor-critic algorithms for finding a good ``reshaping function. In order to demonstrate the learning power of the actor-critic based architecture, we tested it on two experiments: 1 learning to crawl on a humanoid and, 2 learning to gallop on a puppy robot. Two types of actor-critic algorithms (policy search and policy gradient are compared in order to evaluate the advantages and disadvantages of different actor-critic based learning algorithms for different morphologies. Finally, based on the analysis of the experimental results, a generic view/architecture for locomotion learning is discussed in the conclusion.

  17. Effect of plasma jet diameter on the efficiency of reactive oxygen and nitrogen species generation in water

    Science.gov (United States)

    Oh, Jun-Seok; Kakuta, Maito; Furuta, Hiroshi; Akatsuka, Hiroshi; Hatta, Akimitsu

    2016-06-01

    The plasma jet generation of reactive oxygen and nitrogen species (RONS) in solution is important in biology, medicine, and disinfection. Studies using a wide variety of plasma jet devices have been carried out for this purpose, making it difficult to compare the performance between devices. In this study, we compared the efficiency of RONS generation in deionized (DI) water between 3.7-mm- and 800-µm-sized helium (He) plasma jets (hereafter mm-jet and µm-jet, respectively) at different treatment distances and times. The efficiency of RONS generation was determined by considering the total amount of RONS generated in DI water with respect to the input energy and gas consumption. We found that the mm-jet generated 20% more RONS in the DI water than the µm-jet at the optimized distance. However, when the input power and He gas consumption were taken into account, we discovered that the µm-jet was 5 times more efficient in generating RONS in the DI water. Under the parameters investigated in this study, the concentration of RONS continued to increase as a function of treatment time (up to 30 min). However treatment distance had a marked effect on the efficiency of RONS generation: treatment distances of 25 and 30 mm were optimal for the mm-jet and µm-jet, respectively. Our method of comparing the efficiency of RONS generation in solution between plasma jets could be used as a reference protocol for the development of efficient plasma jet sources for use in medicine, biology, and agriculture.

  18. Linear motor system for sliding door for 209-series 950-generation electric railcar; 209 kei 950 dai densha soku hikidoyo rinia motor system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-10

    The system named above has been delivered to East Japan Railway Co. by Fuji Electric Co., Ltd., for use aboard the railway company`s prototype car to close the sliding door and is now in test use, the car designed to carry both commuters and suburbanites. This is the first product of the linear motor-driven type intended to close the sliding door aboard a railway car. Some features are stated below. The door lock and the door lock disengagement unit are improved, with their reliability enhanced. TIMS (train information management system) control and transmission enable the opening and closing of the door, supervision over the individual door state, parameter rewriting, etc., from the driver`s cab. Some base boards are added for shortening the rigging process. It is planned that a 1-linear motor drive system will be manufactured, lighter in weight, lower in power consumption, enhanced in safety, and reduced in cost, for installation aboard the car. (NEDO)

  19. Generation of Volatile Cadmium and Zinc Species Based on Solution Anode Glow Discharge Induced Plasma Electrochemical Processes.

    Science.gov (United States)

    Liu, Xing; Liu, Zhifu; Zhu, Zhenli; He, Dong; Yao, Siqi; Zheng, Hongtao; Hu, Shenghong

    2017-03-21

    In this study, a novel high efficiency vapor generation strategy was proposed on the basis of solution anode glow discharge for the determination of Cd and Zn by atomic fluorescence spectrometry. In this approach, a glow discharge microplasma was acted as a gaseous cathode to initiate the plasma electrochemical vapor generation of Cd and Zn. Cadmium/zinc ions could be converted into molecular species efficiently at the plasma-liquid interface from a supporting electrolyte (HCl, pH = 3.2). It was found that the overall efficiency of the plasma electrochemical vapor generation (PEVG) system was much higher than the conventional electrochemical hydride generation (EcHG) and HCl-KBH4 system. With no requirement for other reducing reagents, this new approach enabled us to detect Cd and Zn with detection limits as low as 0.003 μg L(-1) for Cd and 0.3 μg L(-1) for Zn. Good repeatability (relative standard deviation (RSD), n = 5) was 2.4% for Cd (0.1 μg L(-1)) and 1.7% for Zn (10 μg L(-1)) standard. The accuracy of the proposed method was successfully validated through analysis of cadmium in reference material of stream sediment (GBW07311), soil (GBW07401), rice (GBW10045), and zinc in a simulated water sample (GSB 07-1184-2000). Replacing a metal electrode with a plasma offers the advantage of eliminating potential interactions between the species in liquid and the electrode, which solves the issues associated with electrode encountered in conventional EcHG. The ability to initiate electrochemical vapor generation reactions at the plasma-liquid interface opens a new approach for chemical vapor generation based on interactions between plasma gas-phase electrons and solutions.

  20. Low pressure arc discharges with hollow cathodes and their using in plasma generators and charged particle sources

    CERN Document Server

    Vintizenko, L G; Koval, N N; Tolkachev, V S; Lopatin, I V; Shchanin, P M

    2001-01-01

    Paper presents the results of investigation into arc discharges with a hollow cathode generating 10 sup 1 sup 0 -10 sup 1 sup 2 concentration gas-discharge plasma in essential (approx 1 m sup 3) volumes at low (10 sup - sup 2 -1 Pa) pressures and up to 200 A discharge currents. One studied design of discharge systems with heated and cold cathodes their peculiar features, presented the parameters of plasma generators and of charged particle sources based on arc discharges and discussed, as well, the problems of more rational application of those systems in the processes for surface modification of solids

  1. High-impedance wire grid method to study spatiotemporal behavior of hot electron clump generated in a plasma.

    Science.gov (United States)

    Terasaka, K; Yoshimura, S; Kato, Y; Furuta, K; Aramaki, M; Morisaki, T; Tanaka, M Y

    2014-11-01

    High-impedance Wire Grid (HIWG) detector has been developed to study spatiotemporal behavior of a hot electron clump generated in an electron cyclotron resonance (ECR) plasma. By measuring the floating potentials of the wire electrodes, and generating structure matrix made of geometrical means of the floating potentials, the HIWG detector reconstructs the spatial distribution of high-temperature electron clump at an arbitrary instant of time. Time slices of the spike event in floating potential revealed the growth and decay process of a hot spot occurs in an ECR plasma.

  2. Modeling of defect generation during plasma etching and its impact on electronic device performance—plasma-induced damage

    Science.gov (United States)

    Eriguchi, Koji

    2017-08-01

    The increasing demand for the higher performance of ultra-large-scale integration (ULSI) circuits requires the aggressive shrinkage of device feature sizes in accordance with the scaling law. Plasma processing plays an important role in achieving fine patterns with anisotropic features in metal-oxide-semiconductor field-effect transistors (MOSFETs). This article comprehensively addresses the negative aspects of plasma processing, i.e. plasma process-induced damage, in particular, the defect creation induced by ion bombardment in Si substrates during plasma etching. The ion bombardment damage forms a surface modified region and creates localized defect structures. Modeling and characterization techniques of the ion bombardment damage in Si substrates are overviewed. The thickness of the modified region, i.e. the damaged layer, is modeled by a modified range theory and the density of defects is characterized by photoreflectance spectroscopy (PRS) and the capacitance-voltage technique. The effects of plasma-induced damage (PID) on MOSFET performance are presented. In addition, some of the emerging topics—the enhanced parameter variability in ULSI circuits and recovery of the damage—are discussed as future perspectives.

  3. Whistler Wave generation by an electron beam in a LAPTAG Plasma Physics experiment

    Science.gov (United States)

    Bridges, Gabriel; Pribyl, Patrick; Gekelman, Walter; Thomas, Sam; Birge-Lee, Henry; Wise, Joe; Katz, Cami; Baker, Bob; Marmie, Ken; Wolman, Ben; Buckley-Bonnano, Samuel

    2015-11-01

    A multi-grid pulsed electron beam (Ebeam = 1-4.8 KV, area =1.32 cm2, τ >5 μs) is inserted into a background plasma (He, n = 5X1010 cm3, B0z = 80 G, L = 1.5 m, dia = 40 cm). The pulsed electron beam power supply, can generate up to 4800 Volts at 10 Amps and was constructed by the LAPTAG high school students. The beam can be oriented at any angle with respect to the background magnetic field. The pulsed beam generates whistler waves by Cherenkov radiation. The waves are detected with 3 axis magnetic pickup probes which can be moved in planes transverse or parallel to the background magnetic field under computer control. The whistler wave pattern is used to determine the wavenumber k and Fourier analysis of the signal determines ω. The wave dispersion relation is compared to theory. Work done at BaPSF at UCLA and supported by NSF and DOE.

  4. Magnetic field generation in a jet-sheath plasma via the kinetic Kelvin-Helmholtz instability

    Directory of Open Access Journals (Sweden)

    K.-I. Nishikawa

    2013-09-01

    Full Text Available We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic jet and an unmagnetized sheath plasma. We have examined the strong magnetic fields generated by kinetic shear (Kelvin–Helmholtz instabilities. Compared to the previous studies using counter-streaming performed by Alves et al. (2012, the structure of the kinetic Kelvin–Helmholtz instability (KKHI of our jet-sheath configuration is slightly different, even for the global evolution of the strong transverse magnetic field. In our simulations the major components of growing modes are the electric field Ez, perpendicular to the flow boundary, and the magnetic field By, transverse to the flow direction. After the By component is excited, an induced electric field Ex, parallel to the flow direction, becomes significant. However, other field components remain small. We find that the structure and growth rate of KKHI with mass ratios mi/me = 1836 and mi/me = 20 are similar. In our simulations saturation in the nonlinear stage is not as clear as in counter-streaming cases. The growth rate for a mildly-relativistic jet case (γj = 1.5 is larger than for a relativistic jet case (γj = 15.

  5. Influence of ionic liquid and ionic salt on protein against the reactive species generated using dielectric barrier discharge plasma.

    Science.gov (United States)

    Attri, Pankaj; Sarinont, Thapanut; Kim, Minsup; Amano, Takaaki; Koga, Kazunori; Cho, Art E; Choi, Eun Ha; Shiratani, Masaharu

    2015-12-10

    The presence of salts in biological solution can affect the activity of the reactive species (RS) generated by plasma, and so they can also have an influence on the plasma-induced sterilization. In this work, we assess the influence that diethylammonium dihydrogen phosphate (DEAP), an ionic liquid (IL), and sodium chloride (NaCl), an ionic salt (IS), have on the structural changes in hemoglobin (Hb) in the presence of RS generated using dielectric barrier discharge (DBD) plasma in the presence of various gases [O2, N2, Ar, He, NO (10%) + N2 and Air]. We carry out fluorescence spectroscopy to verify the generation of (•)OH with or without the presence of DEAP IL and IS, and we use electron spin resonance (ESR) to check the generation of H(•) and (•)OH. In addition, we verified the structural changes in the Hb structure after treatment with DBD in presence and absence of IL and IS. We then assessed the structural stability of the Hb in the presence of IL and IS by using molecular dynamic (MD) simulations. Our results indicate that the IL has a strong effect on the conservation of the Hb structure relative to that of IS against RS generated by plasma.

  6. On the role of secondary electrons in beam plasma generation inside a dielectric flask by fore-vacuum plasma-cathode electron source

    Science.gov (United States)

    Zolotukhin, D. B.; Burdovitsin, V. A.; Oks, E. M.

    2017-09-01

    The paper presents the results of experimental research and numerical simulation, demonstrating a considerable influence of secondary electrons on parameters of the beam-produced plasma generated at a pressure range of 1-13 Pa by injection of a continuous (with current of tens mA) electron beam into a dielectric (quartz) flask. An electron beam was formed by a fore-vacuum plasma-cathode electron source based on a hollow cathode discharge. The secondary electrons were emitted as a result of high-energy (3-8 keV) electron beam bombardment mainly a bottom end of the flask. These electrons provide an additional contribution to the ionization of the gas and also affect on the longitudinal distribution of the plasma density along the flask.

  7. Particle Densities of the Atmospheric-Pressure Argon Plasmas Generated by the Pulsed Dielectric Barrier Discharges

    Science.gov (United States)

    Pan, Jie; Li, Li; Wang, Yunuan; Xiu, Xianwu; Wang, Chao; Song, Yuzhi

    2016-11-01

    Atmospheric-pressure argon plasmas have received increasing attention due to their high potential in many industrial and biomedical applications. In this paper, a 1-D fluid model is used for studying the particle density characteristics of the argon plasmas generated by the pulsed dielectric barrier discharges. The temporal evolutions of the axial particle density distributions are illustrated, and the influences of changing the main discharge conditions on the averaged particle densities are researched by independently varying the various discharge conditions. The calculation results show that the electron density and the ion density reach two peaks near the momentary cathodes during the rising and the falling edges of the pulsed voltage. Compared with the charged particle densities, the densities of the resonance state atom Arr and the metastable state atom Arm have more uniform axial distributions, reach higher maximums and decay more slowly. During the platform of the pulsed voltage and the time interval between the pulses, the densities of the excited state atom Ar* are far lower than those of the Arr or the Arm. The averaged particle densities of the different considered particles increase with the increases of the amplitude and the frequency of the pulsed voltage. Narrowing the discharge gap and increasing the relative dielectric constant of the dielectric also contribute to the increase of the averaged particle densities. The effects of reducing the discharge gap distance on the neutral particle densities are more significant than the influences on the charged particle densities. supported by Natural Science Foundation of Shandong Province, China (No. ZR2015AQ008), and Project of Shandong Province Higher Educational Science and Technology Program of China (No. J15LJ04)

  8. Plasma Physics Challenges of MM-to-THz and High Power Microwave Generation

    Science.gov (United States)

    Booske, John

    2007-11-01

    Homeland security and military defense technology considerations have stimulated intense interest in mobile, high power sources of millimeter-wave to terahertz regime electromagnetic radiation, from 0.1 to 10 THz. While sources at the low frequency end, i.e., the gyrotron, have been deployed or are being tested for diverse applications such as WARLOC radar and active denial systems, the challenges for higher frequency sources have yet to be completely met for applications including noninvasive sensing of concealed weapons and dangerous agents, high-data-rate communications, and high resolution spectroscopy and atmospheric sensing. The compact size requirements for many of these high frequency sources requires miniscule, micro-fabricated slow wave circuits with high rf ohmic losses. This necessitates electron beams with not only very small transverse dimensions but also very high current density for adequate gain. Thus, the emerging family of mm-to-THz e-beam-driven vacuum electronics devices share many of the same plasma physics challenges that currently confront ``classic'' high power microwave (HPM) generators [1] including bright electron sources, intense beam transport, energetic electron interaction with surfaces and rf air breakdown at output windows. Multidimensional theoretical and computational models are especially important for understanding and addressing these challenges. The contemporary plasma physics issues, recent achievements, as well as the opportunities and outlook on THz and HPM will be addressed. [1] R.J. Barker, J.H. Booske, N.C. Luhmann, and G.S. Nusinovich, Modern Microwave and Millimeter-Wave Power Electronics (IEEE/Wiley, 2005).

  9. Research on pinches driven by SPPED 2 generator hard X-ray and neutron emission in plasma focus configuration

    CERN Document Server

    Sánchez-Soto, L L; Silva, P; Sylvester, G S; Zambra, M; Pavez, C; Raspa, V; Castillo, F; Kies, W; Soto, Leopoldo; Moreno, Jose; Silva, Patricio; Sylvester, Gustavo; Zambra, Marcelo; Pavez, Cristian; Raspa, Veronica; Castillo, Fermin; Kies, Walter

    2004-01-01

    SPEED2 is a generator based on Marx technology and was designed in the University of Dusseldorf. SPEED2 consists on 40 +/- Marx modules connected in parallel (4.1 mF equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt~1013 A/s). Currently the SPEED2 is operating at the Comision Chilena de Energia Nuclear, CCHEN, Chile, being the most powerful and energetic device for dense transient plasma in the Southern Hemisphere. Most of the previous works developed in SPEED2 at Dusseldorf were done in a plasma focus configuration for soft X-ray emission and the neutron emission from SPEED2 was not completely studied. The research program at CCHEN considers experiments in different pinch configurations (plasma focus, gas puffed plasma focus, gas embedded Z-pinch, wire arrays) at current of hundred of kiloamperes to mega-amperes, using the SPEED2 generator. The Chilean operation has begun implementing and developing diagnostics in a conventional plasma focus configuration oper...

  10. Ablation of boron carbide for high-order harmonic generation of ultrafast pulses in laser-produced plasma

    Science.gov (United States)

    Ganeev, R. A.; Suzuki, M.; Kuroda, H.

    2016-07-01

    We demonstrate the generation of harmonics up to the 27th order (λ=29.9 nm) of 806 nm radiation in the boron carbide plasma. We analyze the advantages and disadvantages of this target compared with the ingredients comprising B4C (solid boron and graphite) by studying the plasma emission and harmonic spectra from three species. We compare different schemes of the two-color pump of B4C plasma, particularly using the second harmonics of 806 nm laser and optical parametric amplifier (1310 nm) as the assistant fields, as well as demonstrate the sum and difference frequency generation using the mixture of the wavelengths of two laser sources. These studies showed the advantages of the two-color pump of B4C plasma leading to the stable harmonic generation and the growth of harmonic conversion efficiency. We also show that the coincidence of harmonic and plasma emission wavelengths in most cases does not cause the enhancement or decrease of the conversion efficiency of this harmonic. Our spatial characterization of harmonics shows their on-axis modification depending on the conditions of frequency conversion.

  11. Generation of disc-like plasma from laser-matter interaction in the presence of a strong external magnetic field

    Science.gov (United States)

    Ivanov, V. V.; Maximov, A. V.; Betti, R.; Wiewior, P. P.; Hakel, P.; Sherrill, M. E.

    2017-08-01

    Dynamics of laser produced plasma in a strong magnetic field was studied using a 1 MA pulsed power generator coupled to an intense, high-energy laser. A 2-2.5 MG magnetic field was generated on the surface of a rod load 0.8-1.2 mm in diameter. A sub-nanosecond laser pulse with intensity of 3 × 1015 W cm-2 was focused on the rod load surface. Side-on laser diagnostics showed the generation of two collimated jets 1-3 mm long on the front and rear sides of the load. End-on laser diagnostics reveal that the laser produced plasma in the MG magnetic field takes the form of a thin disc as the plasma propagates along the magnetic field lines. The disc-like plasma expands radially across the magnetic field with a velocity of 250 km s-1. An electron temperature of 400 eV was measured in the laser-produced plasma on the rod load.

  12. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

    Science.gov (United States)

    Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap--axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  13. Research on pinches driven by Speed-2 generator: Hard X-ray and neutron emission in plasma focus configuration

    Energy Technology Data Exchange (ETDEWEB)

    Soto, L.; Moreno, J.; Silva, P.; Sylvester, G.; Zambra, M.; Pavez, C. [Comision Chilena de Energia Nuclear, Santiago (Chile); Pavez, C. [Universidad de Concepcion (Chile); Raspa, V. [Buenos Aires Univ., PLADEMA, CONICET and INFIP (Argentina); Castillo, F. [Insitituto de Ciencias Nucleares, UNAM (Mexico); Kies, W. [Heinrich-Heine-Univ., Dusseldorf (Germany)

    2004-07-01

    Speed-2 is a generator based on Marx technology and was designed in the University of Dusseldorf. Speed-2 consists on 40 +/- Marx modules connected in parallel (4.1 {mu}F equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt {approx} 10{sup 13} A/s). Currently Speed-2 is operating at CCHEN (Chilean nuclear energy commission), being the most powerful and energetic device for dense transient plasma in the Southern Hemisphere. Most of the previous works developed in Speed-2 at Dusseldorf were done in a plasma focus configuration for soft X-ray emission and the neutron emission from Speed-2 was not completely studied. The research program at CCHEN considers experiments in different pinch configurations (plasma focus, gas puffed plasma focus, gas embedded Z-pinch, wire arrays) at current of hundred of kilo- to mega-amperes, using the Speed-2 generator. The Chilean operation has begun implementing and developing diagnostics in a conventional plasma focus configuration operating in deuterium in order to characterize the neutron emission and the hard X-ray production. Silver activation counters, plastics CR39 and scintillator-photomultiplier detectors are used to characterize the neutron emission. Images of metallic plates with different thickness are obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize an effective energy of the hard X-ray outside of the discharge. (authors)

  14. Improvement of speed profile in induction motor drive using a new idea of PWM pulses generation base on artificial neural networks

    Directory of Open Access Journals (Sweden)

    hojat moayedi rad

    2012-02-01

    Full Text Available Due to simplicity and low cost, induction motors are more useful than direct current motors. Hence the control of these motors is important. The pervious methods are fitted normally for a limited speed range and could not be used for high, low and very low speeds. The voltage model is suitable for high speed because the voltage drop of stator resistance is not small in low speed. The current model is suitable for low speed because of the problems of flux saturation at high speed. This research presents a new method of PWM pulse generating in induction motors based on artificial neural networks in which, the switching pulses are generated by a multilayer feed-forward neural network that is trained by the voltage and current references. Also, for the estimation of required torque and flux information a multilayer perceptron is used. By application of this new method, there is no problem of stability at low and high speeds. The simulation results by matlab-simulink verify the proposed method in transient and steady-state operating modes.

  15. A two-stream plasma electron microwave source for high-power millimeter wave generation, phase 1

    Science.gov (United States)

    Guest, Gareth E.; Dandl, Raphael A.

    1989-03-01

    A novel high power millimeter/microwave source is proposed in which one or more pairs of interpenetrating streams of electrons, flowing through a background plasma in a static magnetic field are used to generate a hot-electron plasma that is confined in a mirror-like magnetic field. Energy stored in the anisotropic, hot-electron plasma is then used to amplify pulses of unstable plasma waves to large amplitude by selective deactivation of mechanisms that stabilize the hot-electron plasma during the energy accumulation phase when the density of hot electrons is rapidly increased through the beam-plasma interaction. The Phase 1 program has yielded a design for an experimental arrangement capable of verifying the key aspects of this novel source concept, as well as a theoretical framework for interpreting the empirical Phase 2 results produced by the experimental device and extrapolating those results to evaluate the suitability of the proposed source to meet the requirements of various high power microwave and millimeter wave defense and industrial applications. The experiments will be carried out in a timely and cost-effective way by employing the AMPHED (a CW magetic mirror) experimental facility at Applied Microwave Plasma Concepts (AMPC).

  16. Sizing modelling and simulation of PV generation system feeding a 6 MW induction motor dedicated to pumping applications

    Directory of Open Access Journals (Sweden)

    Samir HADJERI

    2017-06-01

    Full Text Available This paper proposes an autonomous photovoltaic (PV pumping system for rural/remote applications especially in the large desert in northern Africa where the sun radiation is abundant. Since PV generators exhibit nonlinear I-V characteristics and their maximum power point varies with solar radiation. For this reason, the MPPT controller is used to optimize the solar energy conversion by guaranteeing fast maximum power point tracking (MPPT. This feature has an essential role in dynamic response and efficiency of the photovoltaic system, thus it maximizes the amount of extracted natural gas to be conveyed to another site for an ulterior utilization. Here a robust maximum power point tracker (MPPT using incremental conductance algorithm is applied to the duty cycle value of the DC-DC converter which acts directly on the drive speed. A DC/DC boost is used to enhance voltage up to the favourite level and the SVPWM inverter connects it to a powerful induction motor for a pumping of natural gas application, these systems are at the heart of many industrial sectors such as the oil industry, the production of thermal and nuclear energy etc. An understanding of how these systems operate is essential to increase their performance and reduce their operating costs. Furthermore, three phase voltage-fed PWM inverters are recently showing growing popularity for multi-megawatt industrial drive applications, the main purpose of these topologies is to provide a three-phase voltage source, where the amplitude, phase, and frequency of the voltages should always be controllable. The model of a three-phase voltage source inverter is modelled and discussed based on space vector modulation theory. Simulation results are obtained using MATLAB/Simulink environment for effectiveness of the proposed system.

  17. Blob/hole formation and zonal-flow generation in the edge plasma of the JET tokamak

    DEFF Research Database (Denmark)

    Xu, G.S.; Naulin, Volker; Fundamenski, W.

    2009-01-01

    The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in the edge plasma of the JET tokamak. Holes as well as blobs are observed to be born in the edge shear layer, where zonal-flows shear off meso-scale coherent structures, lead...

  18. Emissions treatment of diesel engines by plasma outside of balance; Tratamiento de emisiones de motores diesel por plasma fuera de equilibrio

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco P, M.; Pacheco S, J.; Valdivia B, R.; Garcia R, M.; Estrada M, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Santana D, A. [Instituto Tecnologico y de Estudios Superiores de Monterrey, Mexico D. F. (Mexico); Lefort, B.; Le Moyne, L.; Zamilpa, C., E-mail: marquidia.pacheco@inin.gob.mx [Institut Superieur d l' Automobile et des Transports, 49 rue Madeimoiselle Bourgeois BP31, 58027 Nevers cedex (France)

    2013-07-01

    Nowadays, diesel engines are greatly developed in automobiles allowing the reduction of carbon dioxide emissions (CO{sub 2}); however high emissions of particulate matter (Mp) and nitric oxides (NO{sub x}) still remain. A technology based on non-thermal plasma to diminish toxic emissions is exposed in this work. From previous experimental and simulation results, a chemical mechanism is proposed showing a rapidly diminution of Mp and NO{sub x}, in presence of plasma. (Author)

  19. Generation of Non-Inductive H-Mode Plasmas with 30 MHz Fast Wave Heating in NSTX-U

    Science.gov (United States)

    Taylor, G.; Bertelli, N.; Gerhardt, S. P.; Hosea, J. C.; Mueller, D.; Perkins, R. J.; Poli, F. M.; Wilson, J. R.; Raman, R.

    2016-10-01

    A Fusion Nuclear Science Facility based on a spherical tokamak must generate the plasma current (Ip) with little or no central solenoid field. The NSTX-U non-inductive (NI) plasma research program is addressing this goal by developing NI start-up, ramp-up and sustainment scenarios separately. 4 MW of 30 MHz fast wave power is predicted to ramp Ip to 400 kA, a level sufficient to avoid significant shine-through of 90 keV ions from neutral beam injection. In 2010, experiments in NSTX demonstrated that 1.4 MW of 30 MHz high-harmonic fast wave (HHFW) power could generate an Ip = 300 kA H-mode discharge with a NI Ip fraction, fNI, around 0.7 at the maximum axial toroidal field (BT(0)) in NSTX of 0.55 T. NSTX-U is a major upgrade of NSTX that will eventually allow the generation of plasmas with BT(0) up to 1 T. Full wave simulations of 30 MHz HHFW heating in NSTX-U predict reduced FW power loss in the plasma edge as BT(0) is increased. HHFW experiments this year aim to couple 3 - 4 MW of 30 MHz HHFW power into an Ip = 250 - 350 kA plasma with BT(0) up to 0.75 T to generate a fNI = 1 H-mode plasma. These experiments should benefit from the improved fast wave coupling predicted at higher BT(0) in NSTX-U. Work supported by USDOE Contract No. DE-AC02-09CH11466.

  20. Generation of longitudinal electric current by the transversal electromagnetic field in classical and quantum plasma

    CERN Document Server

    Latyshev, A V

    2015-01-01

    The analysis of nonlinear interaction of transversal electromagnetic field with degenerate collisionless classical and quantum plasmas is carried out. Formulas for calculation electric current in degenerate collisionless classical and quantum plasmas are deduced. It has appeared, that the nonlinearity account leads to occurrence of longitudinal electric current directed along a wave vector. This second current is orthogonal to the known transversal current, received at the classical linear analysis. Graphic comparison of density of electric current for classical degenerate Fermi plasmas and Fermi-Dirac plasmas (plasmas with any degree of degeneration of electronic gas) is carried out. Graphic comparison of density of electric current for classical and quantum degenerate plasmas is carried out. Also comparison of dependence of density of electric current of quantum degenerate plasmas from dimensionless wave number at various values of dimensionless frequency of oscillations of electromagnetic field is carried ...

  1. Generation of longitudinal electric current by transversal electromagnetic field in Maxwellian plasmas

    CERN Document Server

    Latyshev, A V

    2015-01-01

    The analysis of nonlinear interaction of transversal electromagnetic field with Maxwellian collisionless classical and quntum plasmas is carried out. Formulas for calculation electric current in Maxwellian collisionless classical and quntum plasmas are deduced. It has appeared, that the nonlinearity account leads to occurrence of the longitudinal electric current directed along a wave vector. This second current is orthogonal to the known transversal current, received at the classical linear analysis. Graphic comparison of density of electric current for classical Maxwellian plasmas and Fermi---Dirac plasmas (plasmas with any degree of degeneration of electronic gas) is carried out. Graphic comparison of density of electric current for classical and quantum Maxwellian plasmas is carried out. Also comparison of dependence of density of electric current of quantum Maxwellian plasmas from dimensionless wave number at various values of dimensionless frequency of oscillations of electromagnetic field is carried ou...

  2. Photochemical vapor generation of lead for inductively coupled plasma mass spectrometric detection

    Science.gov (United States)

    Duan, Hualing; Zhang, Ningning; Gong, Zhenbin; Li, Weifeng; Hang, Wei

    2016-06-01

    Photochemical vapor generation (PCVG) of lead was successfully achieved with a simplified and convenient system, in which only low molecular weight organic acid and a high-efficiency photochemical reactor were needed. The reactor was used to generate lead volatile species when a solution of lead containing a small amount of low molecular weight organic acid was pumped through. Several factors, including the concentration of acetic acid, the concentration of hydrochloride acid, and the irradiation time of UV light were optimized. Under the optimal conditions, including the addition of 0.90% (v/v) acetic acid and 0.03% (v/v) hydrochloride acid, and irradiation time of 28 s, intense and repeatable signal of lead volatile species was successfully obtained and identified with inductively coupled plasma mass spectrometry (ICPMS). In addition, the effects from inorganic anions and transition metal ions, including Cl-, NO3-, SO42 -, Cu2 +, Fe3 +, Co2 + and Ni2 +, were investigated, which suggests that their suppression to the PCVG of lead was in the order of Cl- anions and Ni2 +, Co2 + < Fe3 + < Cu2 + for transition metal ions. Under optimized conditions, relative standard derivation (RSD) of 4.4% was achieved from replicate measurements (n = 5) of a standard solution of 0.1 μg L- 1 lead. And, the limit of quantitation (LOQ, 10σ) of 0.012 μg L- 1 lead was obtained using this method and the method blank could be easily controlled down to 0.023 μg L- 1. To validate applicability of this method, it was also employed for the determination of lead in tap water, rain water and lake water.

  3. Thomson Parabola Spectrometer for Energetic Ions Emitted from Sub-ns Laser Generated Plasmas

    Directory of Open Access Journals (Sweden)

    Mariapompea Cutroneo

    2013-01-01

    Full Text Available Laser-generated plasmas were obtained in high vacuum by irradiating micrometric thin films (Au, Au/Mylar, Mylar with the Asterix laser at the PALS Research Infrastructure in Prague. Irradiations at the fundamental wavelength, 300 ps pulse duration, at intensities up to about 1016W/cm2, enabled ions to be accelerated in forward direction with kinetic energies of the order of 2 MeV/charge state. Protons above 2 MeV were obtained in the direction orthogonal to the target surface in selffocusing conditions. Gold ions up to about 120 MeV and 60+ charge state were detected. Ion collectors and semiconductor SiC detectors were employed in time-of-flight arrangement in order to measure the ion velocities as a function of the angle around the normal direction to the target surface. A Thomson parabola spectrometer (TPS with a multi-channel-plate detector was used to separate the different ion contributions to the charge emission in single laser shots, and to get information on the ion charge states, energy and proton acceleration. TPS experimental spectra were compared with accurate TOSCA simulations of TPS parabolas.

  4. Effect of the plasma-generated magnetic field on relativistic electron transport.

    Science.gov (United States)

    Nicolaï, Ph; Feugeas, J-L; Regan, C; Olazabal-Loumé, M; Breil, J; Dubroca, B; Morreeuw, J-P; Tikhonchuk, V

    2011-07-01

    In the fast-ignition scheme, relativistic electrons transport energy from the laser deposition zone to the dense part of the target where the fusion reactions can be ignited. The magnetic fields and electron collisions play an important role in the collimation or defocusing of this electron beam. Detailed description of these effects requires large-scale kinetic calculations and is limited to short time intervals. In this paper, a reduced kinetic model of fast electron transport coupled to the radiation hydrodynamic code is presented. It opens the possibility to carry on hybrid simulations in a time scale of tens of picoseconds or more. It is shown with this code that plasma-generated magnetic fields induced by noncollinear temperature and density gradients may strongly modify electron transport in a time scale of a few picoseconds. These fields tend to defocus the electron beam, reducing the coupling efficiency to the target. This effect, that was not seen before in shorter time simulations, has to be accounted for in any ignition design using electrons as a driver.

  5. High-Resolution THz Measurements of BrO Generated in AN Inductively Coupled Plasma

    Science.gov (United States)

    Nemchick, Deacon J.; Drouin, Brian

    2017-06-01

    Building upon the foundation provided by previous work, the X_{1}^{2}Π_{3/2} and X_{2}^{2}Π_{1/2} states of the transient radical, BrO, were interrogated in previously unprobed spectral regions (0.5 to 1.7 THz) by employing JPL developed high-resolution cascaded frequency multiplier sources. Like other members of the halogen monoxides (XO), this species has been the target of several recent atmospheric remote sensing studies and is a known participant in a catalytic ozone degradation cycle. For the current work, BrO is generated in an inductively coupled plasma under dynamic flow conditions and rotational lines are observed directly at their Doppler-limited resolution. New spectral transitions including those owing to both the ground (ν=0) and excited (ν=1 and 2) vibrational states of isotopologues composed of permutations of natural abundance ^{16}O, ^{18}O, ^{79}Br, and ^{81}Br are fit to a global Hamiltonian containing both fine and hyperfine terms. In addition to further refining existing spectroscopic parameters, new observations will be made available to remote detection communities through addition to the JPL catalog. New findings will be discussed along with future plans to extend these studies to other halogen monoxides (X=Cl and I) and the more massive halogen dioxides (OXO & XOO).

  6. Decontamination effects of low-temperature plasma generated by corona discharge. Part II: new insights.

    Science.gov (United States)

    Scholtz, V; Julák, J; Kríha, V; Mosinger, J; Kopecká, S

    2007-01-01

    The second part of our paper presents the results of experiments with the decontamination of surfaces by low-temperature plasma generated by corona discharge in air at atmospheric pressure. A simple device is described and the effects of the corona discharge on model microorganisms, viz. the yeast Candida albicans, Gram-negative bacteria Escherichia coli, Enterobacter aerogenes, Neisseria sicca, Stenotrophomonas maltophilia, Gram-positive bacteria Deinococcus radiodurans, Enterococcus faecium, Staphylococcus epidermidis, Streptococcus sanguinis, and vegetative and spore forms of Geobacillus stearothermophilus are discussed. A similar microbicidal effect after about one-minute exposure was observed in all vegetative forms of the microorganisms. Measurement in growth inhibition zones on a semisolid medium was used to determine the dependence of the microbicidal effect on exposure time and the distance between electrodes. Counting of colonies served to assess the microbicidal effect of the discharge on contaminated inert surfaces observable after more than 1 min exposure. Geobacillus stearothermophilus spores were found to have several times lower susceptibility to the action of the discharge and the microbicidal effect was observed only after an 8 min exposure. Reaction with the iodide reagent did not unambiguously demonstrate the difference between ozone and singlet oxygen as presumed active components of the corona. The area distribution of reactive oxygen species was determined; it was found to differ from the Wartburg law depending on exposure time. Qualitative evidence was obtained on the penetration of the reactive oxygen species into the semisolid medium.

  7. Issues in Equation of State data generation for Hot Dense MatterA Note on Generalized Radial Mesh Generation for Plasma Electronic Structure

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, B G; Sonnad, V

    2011-02-14

    Precise electronic structure calculations of ions in plasmas benefit from optimized numerical radial meshes. A new closed form expression for obtaining non-linear parameters for the efficient generation of analytic log-linear radial meshes is presented. In conjunction with the (very simple) algorithm for the rapid high precision evaluation of Lambert's W-function, the above identity allows the precise construction of generalized log-linear radial meshes adapted to various constraints.

  8. Higher Plasma LDL-Cholesterol is Associated with Preserved Executive and Fine Motor Functions in Parkinson’s Disease

    OpenAIRE

    Sterling, Nicholas W.; Lichtenstein, Maya; Lee, Eun-Young; Lewis, Mechelle M.; Evans, Alicia; Eslinger, Paul J.; Du, Guangwei; Gao, Xiang; Chen, Honglei; Kong, Lan; Huang, Xuemei

    2016-01-01

    Plasma low density lipoprotein (LDL) cholesterol has been associated both with risk of Parkinson’s disease (PD) and with age-related changes in cognitive function. This prospective study examined the relationship between baseline plasma LDL-cholesterol and cognitive changes in PD and matched Controls. Fasting plasma LDL-cholesterol levels were obtained at baseline from 64 non-demented PD subjects (62.7 ± 7.9 y) and 64 Controls (61.3 ± 6.8 y). Subjects underwent comprehensive neuropsychologica...

  9. The Research on Atmospheric Pressure Water Vapour Plasma Generation and Application for the Destruction of Wastes

    Directory of Open Access Journals (Sweden)

    Viktorija Grigaitiene

    2013-01-01

    Full Text Available In the Lithuanian Energy Institute an experimental atmospheric pressure Ar/water vapour plasma torch has been designed and tested. The power of plasma torch was estimated 40 ÷ 69 kW, the mean temperature of plasma jet at the exhaust nozzle was 2300÷2900K. The chemical compositionof water vapour plasma was established from the emission spectrum lines at 300 ÷ 800nm range. The main species observed in Ar/water vapour plasma were: Ar, OH, H, O, Cu. The experiments on water vapour steam reforming were performed. The results confirmed that water vapour plasma has the unique properties – high enthalpy and environmentally friendly conditions. It could be employed for environmental purposes such as destruction of wastes into simple molecules or conversion to synthetic gas.

  10. Treatment of liquid wastes generated by maintenance operations applied to motor vehicles; Tratamiento de residuos liquidos generados en las operaciones de mantenimiento de vehiculos a motor

    Energy Technology Data Exchange (ETDEWEB)

    Lloret i Bosca, G.; Boch Mossi, F.; Oyonarte Andres, S.; Colomer Signes, S.; Soro Casanova, J. R.

    2007-07-01

    The Life European project Urban-Bat presents an innovating approach to liquid wastes generated by maintenance operations applied to bus fleets by defining, through implementation of Best Available Technologies (Bat), a waste management model based on reduction of environmental impact and on life span increase of raw materials. This will take place at the very point of generation thus minimizing the need for an external waste management. (Author) 5 refs.

  11. Enhancement of Limb Growth by Non-Thermal Plasma Generated Reactive Species

    Science.gov (United States)

    Shainsky, N.; Steinbeck, M.; Fridman, G.; Fridman, A.; Friedman, G.; Freeman, T.

    2013-09-01

    Introduction: The goal of this investigation was to examine the effect of Dielectric Barrier Discharge plasma on mouse autopod differentiation and growth. In this study we hypothesized that NT-plasma can be used to promote redox dependent changes in differentiation pathways and enhance developmental signaling? Methods: Approximately 1 hour after isolation, NT-plasma or sham plasma treatment was applied to the right or left limb, respectively. The medium was changed daily thereafter for the 4-6 days of culture. NT-plasma treatment: pulsed (1000 Hz) voltage of 17 - 25 kV magnitude (peak to peak), a 1 μs pulse width and a rise time of 5 V/ns between the quartz-insulated high voltage electrode and the sample undergoing treatment. Results: A single 10 second NT-plasma treatment promoted development of mouse autopods as compared to the sham control contralateral limb. NT-plasma accelerated digit growth in both E14.5 and E12.5 autopods. Inhibitors were used to determine the role of ROS and RNS in mediating NT-plasma accelerated autopod development. Treatment with these agents stunted autopod morphogenesis NT-plasma treatment partially rescued development. Discussion: Our findings highlight the capability of NT-plasma to activate ROS-dependent cell signaling cascades within developing autopod tissue. In fact, the effect of NT-plasma may indeed extend beyond ROS sensitive signaling as NT-plasma exposure seems to stimulate some growth even in the presence of antioxidant induced stunting. This work was supported by NIH Grants 1 R01 EB 013011 - 01 (Freeman and G. Fridman).

  12. The theta-pinch - a versatile tool for the generation and study of high temperature plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hintz, E. [Inst. fuer Plasmaphysik, Forschungszentrum-Juelich GmbH (Germany)

    2004-07-01

    The more general technical and physical features of theta-pinches are described. Special field of their application are high-ss plasmas. Two examples are analysed and studied in more detail: a high density plasma near thermal equilibrium and a low density plasma far from equilibrium. The latter is of special interest for future investigations. Possibilities of field-reversed configurations are pointed out. (orig.)

  13. Cell death induced on cell cultures and nude mouse skin by non-thermal, nanosecond-pulsed generated plasma.

    Directory of Open Access Journals (Sweden)

    Arnaud Duval

    Full Text Available Non-thermal plasmas are gaseous mixtures of molecules, radicals, and excited species with a small proportion of ions and energetic electrons. Non-thermal plasmas can be generated with any high electro-magnetic field. We studied here the pathological effects, and in particular cell death, induced by nanosecond-pulsed high voltage generated plasmas homogeneously applied on cell cultures and nude mouse skin. In vitro, Jurkat cells and HMEC exhibited apoptosis and necrosis, in dose-dependent manner. In vivo, on nude mouse skin, cell death occurred for doses above 113 J/cm(2 for the epidermis, 281 J/cm(2 for the dermis, and 394 J/cm(2 for the hypodermis. Using electron microscopy, we characterized apoptosis for low doses and necrosis for high doses. We demonstrated that these effects were not related to thermal, photonic or pH variations, and were due to the production of free radicals. The ability of cold plasmas to generate apoptosis on cells in suspension and, without any sensitizer, on precise skin areas, opens new fields of application in dermatology for extracorporeal blood cell treatment and the eradication of superficial skin lesions.

  14. Degradation of perfluoro compounds and f{sup -} recovery in water using discharge plasmas generated within gas bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Yasuoka, K.; Sasaki, K.; Hayashi, R.; Kosugi, A.; Takeuchi, N. [Tokyo Inst. of Technology, Tokyo (Japan). Dept. of Electrical and Electronic Engineering

    2010-07-01

    The widespread use of perfluorocarbons (PFCs) has raised environmental concerns because of their chemical stability and the toxicity of long-chain PFCs. Since PFCs such as perfluorooctanoic acid (PFOA) or perfluorooctanesulfonic acid (PFOS) cannot be decomposed by advanced oxidation technologies utilizing OH radicals, other methods have been tested to decompose their strong C-F bonds. Recent studies have shown that direct plasma-water interaction can easily decompose such persistent substances in water. A DC plasma generated within oxygen bubbles in water showed a higher decomposition rate and efficiency than pulsed plasmas. During decomposition, fluorine ions were generated in the solution. The recovery of fluorine from PFOA in water was tested by combining the PFOA decomposition process and calcium precipitation method. The recovery of fluorine is important due to the increasing price of fluorite. The PFC decomposing rate and efficiency were evaluated by measuring the fluorine ions generated in the solution. The decomposing rate for PFOA was slightly higher than that for PFOS. The direct plasma interaction to the solution surfaces appeared to enhance the degradation of PFOA/PFOS. 10 refs., 1 tab., 9 figs.

  15. Subtarget Effect on Laser Plasma Generated by Transversely Excited Atmospheric CO2 Laser at Atmospheric Gas Pressure

    Science.gov (United States)

    Kagawa, Kiichiro; Lie, Tjung Jie; Hedwig, Rinda; Abdulmajid, Syahrun Nur; Suliyanti, Maria Margaretha; Kurniawan, Hendrik

    2000-05-01

    An experimental study has been carried out on the dynamical process taking place in the laser plasma generated by Transversely Excited Atmospheric CO2 laser (100 mJ, 50 ns) irradiation of a soft sample at surrounding helium pressure of 1 atm. It is shown that the presence of a copper subtarget behind the soft sample is crucial in raising the gushing speed of the atoms to the level adequate for the generation of shock wave laser plasma even at atmospheric pressure. It is also found that the time profiles of spatially integrated emission intensity of the target’s atoms and gas atoms exhibit a characteristic dynamical process that consists of successive excitation and cooling stages even at such a high pressure, which is typical of shock wave laser plasma. It is therefore suggested that the generation of the laser plasma at atmospheric pressure is more likely due to the shock wave mechanism than to the widely known breakdown mechanism. Initial spectrochemical analysis of water from the blow off of a boiler system was also carried out, showing a detection limit of as low as 5 ppm for calcium.

  16. On the frequency of oscillations in the pair plasma generated by a strong electric field

    CERN Document Server

    Benedetti, A; Ruffini, R; Vereshchagin, G V

    2011-01-01

    We study the frequency of the plasma oscillations of electron-positron pairs created by the vacuum polarization in an uniform electric field with strength E in the range 0.2 Ec 0. Thereby, we focus our attention on its evolution in time studying how this oscillation frequency approaches the plasma frequency. The time-scale needed to approach to the plasma frequency and the power spectrum of these oscillations are computed. The characteristic frequency of the power spectrum is determined uniquely from the initial value of the electric field strength. The effects of plasma degeneracy and pair annihilation are discussed.

  17. Generation and pointing stabilization of multi-GeV electron beams from a laser plasma accelerator driven in a pre-formed plasma waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Gonsalves, A. J.; Nakamura, K.; Daniels, J.; Mao, H.-S.; Benedetti, C.; Schroeder, C. B.; Tóth, Cs.; Tilborg, J. van; Vay, J.-L.; Geddes, C. G. R.; Esarey, E. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Mittelberger, D. E.; Bulanov, S. S.; Leemans, W. P., E-mail: WPLeemans@lbl.gov [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

    2015-05-15

    Laser pulses with peak power 0.3 PW were used to generate electron beams with energy >4 GeV within a 9 cm-long capillary discharge waveguide operated with a plasma density of ≈7×10{sup 17} cm{sup −3}. Simulations showed that the super-Gaussian near-field laser profile that is typical of high-power femtosecond laser systems reduces the efficacy of guiding in parabolic plasma channels compared with the Gaussian laser pulses that are typically simulated. In the experiments, this was mitigated by increasing the plasma density and hence the contribution of self-guiding. This allowed for the generation of multi-GeV electron beams, but these had angular fluctuation ≳2 mrad rms. Mitigation of capillary damage and more accurate alignment allowed for stable beams to be produced with energy 2.7±0.1 GeV. The pointing fluctuation was 0.6 mrad rms, which was less than the beam divergence of ≲1 mrad full-width-half-maximum.

  18. Trial of Growth Control of Farm-raised Fish by Plasma-generated Reactive Species

    Science.gov (United States)

    Motomura, Hideki; Kubota, Yoshiki; Fukushima, Ryo; Ikeda, Yoshihisa; Jinno, Masafumi

    2016-09-01

    As one of the biological applications of plasmas, growth control of agricultural products attracts attentions. There are many papers on growth enhancement of crops by plasma treatment. However, there are few published papers concerning growth enhancement of fishery products excepting reports of goldfish growth enhancement in 1980s. In this study, growth characteristics of edible fish (tilapia) under the plasma treatment has been investigated. An arc discharge reactor was employed and plasma treated air was introduced to two aquariums with a flow rate of 2.5 L/min. Measured concentrations of main reactive species were 43 ppm for NO, 23 ppm for NO2 and 7.5 ppm for O3. Each aquarium had 60 L capacity and contained 15 tilapia fish. The plasma treated air was supplied to an aquarium once a day and to the other aquarium twice a day with total duration of 10 min. Compared to no plasma treatment case, the growth rate decreased by 18% by once a day plasma treatment, whereas almost same growth rate was observed by twice a day plasma treatment. A possible reason of growth suppression is excess concentrations of nitrite and nitrate in water. The relationship between their concentrations and growth characteristics under several treatment conditions will be shown at the conference. Tirapia fish was supplied from SEFREC of Ehime University.

  19. Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

    Science.gov (United States)

    Sydorenko, Dmytro; Kaganovich, Igor D.; Ventzek, Peter L. G.

    2016-10-01

    Electrons emitted from electrodes are accelerated by the sheath electric field and become the electron beams penetrating the plasma. The electron beam can interact with the plasma in collisionless manner via two-stream instability and produce suprathermal electrons. In order to understand the mechanism of suprathermal electrons acceleration, a beam-plasma system was simulated using a 1D3V particle-in-cell code EDIPIC. These simulation results show that the acceleration may be caused by the effects related to the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. Rich complexity of beam- plasma interaction phenomena was also observed: intermittency and multiple regimes of two-stream instability in a dc discharge, band structure of the growth rate of the two-stream instability of an electron beam propagating in a bounded plasma, multi-stage acceleration of electrons in a finite system.

  20. Numerical study of extreme-ultra-violet generated plasmas in hydrogen

    NARCIS (Netherlands)

    Astakhov, Dmitry

    2016-01-01

    In this thesis, we present the development and study a numerical model of EUV-induced plasma. Understanding of behavior of low pressure low density plasmas is of industrial relevance, because of their potential use for on-line removal of different forms of contaminations from multilayer mirrors, whi

  1. Ablation of Barrett's esophagus using the second-generation argon plasma coagulation

    Institute of Scientific and Technical Information of China (English)

    Li Zhang; Lei Dong; Jia Liu; Xiao-lan Lu

    2009-01-01

    Objective To investigate the efficacy and safety of the second-generation argon plasma coagulation (VIO APC) in ablation of Barrett's esophagus. Methods Eighteen patients with Barrett's esophagus (12 males, median age of 55 years, median length of 2.1 cm,1 low-grade dysplasia, 13 cases of short segment Barrett's esophagus) received VIO APC, which was performed at a power setting of 40W and argon gas flow at 1. 5-2. 0 L/min, "forced" mode, in 1-3 sessions (mean 1.3). All the patients received treatment with high-dose proton pump inhibitors. The main complaints before ablation were upper abdominal pain in 12 patients (66%), sour regurgitation in 14 patients (77%), and dysphagia or odynophagia in 7 patients (38%). Two patients (11%) had esophageal hiatal hernia. Results The percentage of patients in whom ablation was endoscopically achieved proximal to the gastroesophageal junction was 77. 8%(14/18), and histologically achieved in 66. 7% (12/18). Berried glands were observed in 2 patients who had achieved endoscopic ablation, the areas of Barrett's mucosa were reduced by more than 60% in the other 4 patients. After treatment, 4 patients had transient retrosternal pain and 3 patients had mild epigastric discomfort. One patient had small amounts of hemorrhage during the process, and it ceased after norepinephrine and thrombosin were administered through endoscope biopsy channel. No esophageal stricture or other severe adverse events was observed. During 11.8 (4-15) months' follow-up, the patients who had achieved the complete ablation had no evidence of relapse of Barrett's esophagus. Conclusion VIO APC with a relatively low power setting can effectively ablate the Barrett's mucosa with special intestinal metaplasia when standard APC has been done. No severe adverse events were observed. Long-term follow-up is needed to assess cancer prevention and the durability of the neo-squamous epithelium.

  2. Cold Atmospheric Plasma Generated in Water and its Potential Use in Cancer Therapy

    CERN Document Server

    Chen, Zhitong; Lin, Li; Keidar, Michael

    2016-01-01

    Cold atmospheric plasma (CAP) has been emerged as a novel technology for cancer treatment. CAP can directly treat cells and tissue but such direct application is limited to skin or can be invoked as a supplement during open surgery. In this letter we report indirect plasma treatment using CAP produced in a water using three gases as carrier (argon, helium and nitrogen). Plasma stimulated water was applied to human breast cancer cell line (MDA-MB-231). MTT assays tests showed that using argon plasma had the strongest effect on inducing apoptosis in cultured human breast cancer cells. This result is attributed to the elevated production of the reactive oxygen species and reactive nitrogen species in water in the case of argon plasma.

  3. Generation of neutral and high-density electron–positron pair plasmas in the laboratory

    Science.gov (United States)

    Sarri, G.; Poder, K.; Cole, J. M.; Schumaker, W.; Di Piazza, A.; Reville, B.; Dzelzainis, T.; Doria, D.; Gizzi, L. A.; Grittani, G.; Kar, S.; Keitel, C. H.; Krushelnick, K.; Kuschel, S.; Mangles, S. P. D.; Najmudin, Z.; Shukla, N.; Silva, L. O.; Symes, D.; Thomas, A. G. R.; Vargas, M.; Vieira, J.; Zepf, M.

    2015-01-01

    Electron–positron pair plasmas represent a unique state of matter, whereby there exists an intrinsic and complete symmetry between negatively charged (matter) and positively charged (antimatter) particles. These plasmas play a fundamental role in the dynamics of ultra-massive astrophysical objects and are believed to be associated with the emission of ultra-bright gamma-ray bursts. Despite extensive theoretical modelling, our knowledge of this state of matter is still speculative, owing to the extreme difficulty in recreating neutral matter–antimatter plasmas in the laboratory. Here we show that, by using a compact laser-driven setup, ion-free electron–positron plasmas with unique characteristics can be produced. Their charge neutrality (same amount of matter and antimatter), high-density and small divergence finally open up the possibility of studying electron–positron plasmas in controlled laboratory experiments. PMID:25903920

  4. Large diameter permanent-magnets-expanded plasma source for spontaneous generation of low-energy ion beam.

    Science.gov (United States)

    Takahashi, Kazunori; Suzuki, Tatsuya; Ando, Akira

    2014-02-01

    Diameter of a permanent-magnets-expanded, radiofrequency (rf) plasma source is enlarged up to ∼13 cm for an application to a space propulsion device and tested with being attached to a diffusion chamber. The source is operated at 13.56 MHz 300 W rf power in low-pressure (40 mPa) argon. Measurement of ion energy distribution functions downstream of the source exit shows generation of a supersonic ion beam of about 20 eV. The detailed radial measurements demonstrate that the diameter and energy of the ion beam corresponds to the source tube diameter and the potential difference between the source and downstream plasmas, and that the radial profile of the beam flux is similar to the plasma density profile in the source cavity.

  5. The TELEC - A plasma type of direct energy converter. [Thermo-Electronic Laser Energy Converter for electric power generation

    Science.gov (United States)

    Britt, E. J.

    1978-01-01

    The Thermo-Electronic Laser Energy Converter (TELEC) is a high-power density plasma device designed to convert a 10.6-micron CO2 laser beam into electric power. Electromagnetic radiation is absorbed in plasma electrons, creating a high-electron temperature. Energetic electrons diffuse from the plasma and strike two electrodes having different areas. The larger electrode collects more electrons and there is a net transport of current. An electromagnetic field is generated in the external circuit. A computer program has been designed to analyze TELEC performance allowing parametric variation for optimization. Values are presented for TELEC performance as a function of cesium pressure and for current density and efficiency as a function of output voltage. Efficiency is shown to increase with pressure, reaching a maximum over 45%.

  6. Generation of acoustic rogue waves in dusty plasmas through three-dimensional particle focusing by distorted waveforms

    Science.gov (United States)

    Tsai, Ya-Yi; Tsai, Jun-Yi; I, Lin

    2016-06-01

    Rogue waves--rare uncertainly emerging localized events with large amplitudes--have been experimentally observed in many nonlinear wave phenomena, such as water waves, optical waves, second sound in superfluid He II (ref. ) and ion acoustic waves in plasmas. Past studies have mainly focused on one-dimensional (1D) wave behaviour through modulation instabilities, and to a lesser extent on higher-dimensional behaviour. The question whether rogue waves also exist in nonlinear 3D acoustic-type plasma waves, the kinetic origin of their formation and their correlation with surrounding 3D waveforms are unexplored fundamental issues. Here we report the direct experimental observation of dust acoustic rogue waves in dusty plasmas and construct a picture of 3D particle focusing by the surrounding tilted and ruptured wave crests, associated with the higher probability of low-amplitude holes for rogue-wave generation.

  7. Mortality from Alzheimer's, motor neuron and Parkinson's disease in relation to magnetic field exposure: findings from the study of UK electricity generation and transmission workers, 1973-2004.

    Science.gov (United States)

    Sorahan, T; Kheifets, L

    2007-12-01

    There are a number of reports linking magnetic field exposure to increased risks of Alzheimer's disease and motor neuron disease. The mortality experienced by a cohort of 83 997 employees of the former Central Electricity Generating Board of England and Wales was investigated for the period 1973-2004. All employees were employed for at least six months with some employment in the period 1973-82. Computerised work histories were available for 79 972 study subjects for the period 1971-93. Information on job and facility (location) were used to estimate exposures to magnetic fields. Two analytical approaches were used to evaluate risks, indirect standardisation (n = 83 997) and Poisson regression (n = 79 972). Based on serial mortality rates for England and Wales, deaths from Alzheimer's disease and motor neuron disease were unexceptional. There was an excess of deaths from Parkinson's disease of borderline significance. No statistically significant trends were shown for risks of any of these diseases to increase with lifetime cumulative exposure to magnetic fields (RR per 10 μT-y: Alzheimer's disease 1.10 (95% CI 0.90 to 1.33); motor neuron disease 1.06 (95% CI 0.86 to 1.32); Parkinson's disease 0.88 (95% CI 0.74 to 1.05)) There is no convincing evidence that UK electricity generation and transmission workers have suffered increased risks from neurodegenerative diseases as a consequence of exposure to magnetic fields.

  8. Elevated mRNA-levels of distinct mitochondrial and plasma membrane Ca2+ transporters in individual hypoglossal motor neurons of endstage SOD1 transgenic mice.

    Directory of Open Access Journals (Sweden)

    Tobias eMühling

    2014-11-01

    Full Text Available Disturbances in Ca2+ homeostasis and mitochondrial dysfunction have emerged as major pathogenic features in familial and sporadic forms of Amyotrophic Lateral Sclerosis (ALS, a fatal degenerative motor neuron disease. However, the distinct molecular ALS-pathology remains unclear. Recently, an activity-dependent Ca2+ homeostasis deficit, selectively in highly vulnerable cholinergic motor neurons in the hypoglossal nucleus (hMNs from a common ALS mouse model, endstage superoxide dismutase SOD1G93A transgenic mice, was described. This functional deficit was defined by a reduced hMN mitochondrial Ca2+ uptake capacity and elevated Ca2+ extrusion across the plasma membrane. To address the underlying molecular mechanisms, here we quantified mRNA-levels of respective potential mitochondrial and plasma membrane Ca2+ transporters in individual, choline-acetyltransferase (ChAT positive hMNs from wildtype (WT and endstage SOD1G93A mice, by combining UV laser microdissection with RT-qPCR techniques, and specific data normalization. As ChAT cDNA levels as well as cDNA and genomic DNA levels of the mitochondrially encoded NADH dehydrogenase ND1 were not different between hMNs from WT and endstage SOD1G93A mice, these genes were used to normalize hMN-specific mRNA-levels of plasma membrane and mitochondrial Ca2+ transporters, respectively. We detected about 2-fold higher levels of the mitochondrial Ca2+ transporters MCU/MICU1, Letm1 and UCP2 in remaining hMNs from endstage SOD1G93A mice. These higher expression-levels of mitochondrial Ca2+ transporters in individual hMNs were not associated with a respective increase in number of mitochondrial genomes, as evident from hMN specific ND1 DNA quantification. Normalized mRNA-levels for the plasma membrane Na2+/Ca2+exchanger NCX1 was also about 2-fold higher in hMNs from SOD1G93A mice. Thus, pharmacological stimulation of Ca2+ transporters in highly vulnerable hMNs might offer a novel neuroprotective strategy for ALS.

  9. Chemical kinetics and relaxation of non-equilibrium air plasma generated by energetic photon and electron beams

    Science.gov (United States)

    Maulois, Melissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Azaïs, Bruno

    2016-04-01

    The comprehension of electromagnetic perturbations of electronic devices, due to air plasma-induced electromagnetic field, requires a thorough study on air plasma. In the aim to understand the phenomena at the origin of the formation of non-equilibrium air plasma, we simulate, using a volume average chemical kinetics model (0D model), the time evolution of a non-equilibrium air plasma generated by an energetic X-ray flash. The simulation is undertaken in synthetic air (80% N2 and 20% O2) at ambient temperature and atmospheric pressure. When the X-ray flash crosses the gas, non-relativistic Compton electrons (low energy) and a relativistic Compton electron beam (high energy) are simultaneously generated and interact with the gas. The considered chemical kinetics scheme involves 26 influent species (electrons, positive ions, negative ions, and neutral atoms and molecules in their ground or metastable excited states) reacting following 164 selected reactions. The kinetics model describing the plasma chemistry was coupled to the conservation equation of the electron mean energy, in order to calculate at each time step of the non-equilibrium plasma evolution, the coefficients of reactions involving electrons while the energy of the heavy species (positive and negative ions and neutral atoms and molecules) is assumed remaining close to ambient temperature. It has been shown that it is the relativistic Compton electron beam directly created by the X-ray flash which is mainly responsible for the non-equilibrium plasma formation. Indeed, the low energy electrons (i.e., the non-relativistic ones) directly ejected from molecules by Compton collisions contribute to less than 1% on the creation of electrons in the plasma. In our simulation conditions, a non-equilibrium plasma with a low electron mean energy close to 1 eV and a concentration of charged species close to 1013 cm-3 is formed a few nanoseconds after the peak of X-ray flash intensity. 200 ns after the flash

  10. Two interconnected kernels of reciprocally inhibitory interneurons underlie alternating left-right swim motor pattern generation in the mollusk Melibe leonina.

    Science.gov (United States)

    Sakurai, Akira; Gunaratne, Charuni A; Katz, Paul S

    2014-09-15

    The central pattern generator (CPG) underlying the rhythmic swimming behavior of the nudibranch Melibe leonina (Mollusca, Gastropoda, Heterobranchia) has been described as a simple half-center oscillator consisting of two reciprocally inhibitory pairs of interneurons called swim interneuron 1 (Si1) and swim interneuron 2 (Si2). In this study, we identified two additional pairs of interneurons that are part of the swim CPG: swim interneuron 3 (Si3) and swim interneuron 4 (Si4). The somata of Si3 and Si4 were both located in the pedal ganglion, near that of Si2, and both had axons that projected through the pedal commissure to the contralateral pedal ganglion. These neurons fulfilled the criteria for inclusion as members of the swim CPG: 1) they fired at a fixed phase in relation to Si1 and Si2, 2) brief changes in their activity reset the motor pattern, 3) prolonged changes in their activity altered the periodicity of the motor pattern, 4) they had monosynaptic connections with each other and with Si1 and Si2, and 5) their synaptic actions helped explain the phasing of the motor pattern. The results of this study show that the motor pattern has more complex internal dynamics than a simple left/right alternation of firing; the CPG circuit appears to be composed of two kernels of reciprocally inhibitory neurons, one consisting of Si1, Si2, and the contralateral Si4 and the other consisting of Si3. These two kernels interact with each other to produce a stable rhythmic motor pattern.

  11. High efficiency motors; Motores de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)

    1992-12-31

    This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.

  12. Compressed air storage concept BOP-B - Heat-exchanger and motor-generator; Machbarkeit des Druckluftspeicherkonzeptes BOP-B. Waermetauscher und Motgen

    Energy Technology Data Exchange (ETDEWEB)

    Brueckmann, P. [Brueckmann Elektronik, Davos Dorf (Switzerland); Cyphelly, I. [Cyphelly and Cie, Les Brenets (Switzerland); Lindegger, M. [Circle Motor AG, Guemligen (Switzerland)

    2006-11-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) deals with project concerning a compressed-air energy storage system. The authors state that the BOP-B is a highly efficient compressor or air motor and can work efficiently if the compression or expansion of the air takes place in a mostly isothermal way. First tests made on the heat-exchanger unit are reported on and conclusions are drawn. A second part of the paper deals with the motor-generator unit (Motgen). The mechanical and electrical construction of the Motgen is described along with the results of tests performed on the unit. The results of measurements made are presented and discussed.

  13. Rocket motor exhaust products generated by the space shuttle vehicle during its launch phase (1976 design data)

    Science.gov (United States)

    Bowyer, J. M.

    1977-01-01

    The principal chemical species emitted and/or entrained by the rocket motors of the space shuttle vehicle during the launch phase of its trajectory are considered. Results are presented for two extreme trajectories, both of which were calculated in 1976.

  14. Influence of reactive species on the modification of biomolecules generated from the soft plasma.

    Science.gov (United States)

    Attri, Pankaj; Kumar, Naresh; Park, Ji Hoon; Yadav, Dharmendra Kumar; Choi, Sooho; Uhm, Han S; Kim, In Tae; Choi, Eun Ha; Lee, Weontae

    2015-02-04

    Plasma medicine is an upcoming research area that has attracted the scientists to explore more deeply the utility of plasma. So, apart from the treating biomaterials and tissues with plasma, we have studied the effect of soft plasma with different feeding gases such as Air, N2 and Ar on modification of biomolecules. Hence, in this work we have used the soft plasma on biomolecules such as proteins ((Hemoglobin (Hb) and Myoglobin (Mb)), calf thymus DNA and amino acids. The structural changes or structural modification of proteins and DNA have been studied using circular dichroism (CD), fluorescence spectroscopy, protein oxidation test, gel electrophoresis, UV-vis spectroscopy, dynamic light scattering (DLS) and 1D NMR, while Liquid Chromatograph/Capillary Electrophoresis-Mass Spectrometer (LC/CE-MS) based on qualitative and quantitative bio-analysis have been used to study the modification of amino acids. Further, the thermal analysis of the protein has been studied with differential scanning calorimetry (DSC) and CD. Additionally, we have performed docking studies of H2O2 with Hb and Mb, which reveals that H2O2 molecules preferably attack the amino acids near heme group. We have also shown that N2 gas plasma has strong deformation action on biomolecules and compared to other gases plasma.

  15. Influence of reactive species on the modification of biomolecules generated from the soft plasma

    Science.gov (United States)

    Attri, Pankaj; Kumar, Naresh; Park, Ji Hoon; Yadav, Dharmendra Kumar; Choi, Sooho; Uhm, Han S.; Kim, In Tae; Choi, Eun Ha; Lee, Weontae

    2015-02-01

    Plasma medicine is an upcoming research area that has attracted the scientists to explore more deeply the utility of plasma. So, apart from the treating biomaterials and tissues with plasma, we have studied the effect of soft plasma with different feeding gases such as Air, N2 and Ar on modification of biomolecules. Hence, in this work we have used the soft plasma on biomolecules such as proteins ((Hemoglobin (Hb) and Myoglobin (Mb)), calf thymus DNA and amino acids. The structural changes or structural modification of proteins and DNA have been studied using circular dichroism (CD), fluorescence spectroscopy, protein oxidation test, gel electrophoresis, UV-vis spectroscopy, dynamic light scattering (DLS) and 1D NMR, while Liquid Chromatograph/Capillary Electrophoresis-Mass Spectrometer (LC/CE-MS) based on qualitative and quantitative bio-analysis have been used to study the modification of amino acids. Further, the thermal analysis of the protein has been studied with differential scanning calorimetry (DSC) and CD. Additionally, we have performed docking studies of H2O2 with Hb and Mb, which reveals that H2O2 molecules preferably attack the amino acids near heme group. We have also shown that N2 gas plasma has strong deformation action on biomolecules and compared to other gases plasma.

  16. Second harmonic generation of q-Gaussian laser beam in preformed collisional plasma channel with nonlinear absorption

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Naveen, E-mail: naveens222@rediffmail.com; Singh, Arvinder, E-mail: arvinder6@lycos.com [Department of Physics, National Institute of Technology Jalandhar (India); Singh, Navpreet, E-mail: navpreet.nit@gmail.com [Guru Nanak Dev University College, Kapurthala, Punjab (India)

    2015-11-15

    This paper presents a scheme for second harmonic generation of an intense q-Gaussian laser beam in a preformed parabolic plasma channel, where collisional nonlinearity is operative with nonlinear absorption. Due to nonuniform irradiance of intensity along the wavefront of the laser beam, nonuniform Ohmic heating of plasma electrons takes place. Due to this nonuniform heating of plasma, the laser beam gets self-focused and produces strong density gradients in the transverse direction. The generated density gradients excite an electron plasma wave at pump frequency that interacts with the pump beam to produce its second harmonics. The formulation is based on a numerical solution of the nonlinear Schrodinger wave equation in WKB approximation followed by moment theory approach. A second order nonlinear differential equation governing the propagation dynamics of the laser beam with distance of propagation has been obtained and is solved numerically by Runge Kutta fourth order technique. The effect of nonlinear absorption on self-focusing of the laser beam and conversion efficiency of its second harmonics has been investigated.

  17. Third Harmonic Generation of a Short Pulse Laser in a Tunnel Ionizing Plasma: Effect of Self-Defocusing

    Directory of Open Access Journals (Sweden)

    Niti Kant

    2013-08-01

    Full Text Available Third harmonic generation of a Gaussian short pulse laser in a tunnel ionizing plasma is investigated. A Gaussian short pulse laser propagating through a tunnel ionizing plasma generates third harmonic wave. Inhomogeneity of the electric field along the wavefront of the fundamental laser pulse causes more ionization along the axis of propagation while less ionization off axis, leading to strong density gradient with its maximum on the axis of propagation. The medium acts like a diverging lens and pulse defocuses strongly. The normalized third harmonic amplitude varies periodically with the distance with successive maxima acquiring lower value. The self-defocusing of the fundamental laser pulse decays the intensity of the third harmonic pulse.

  18. Transport simulations of linear plasma generators with the B2.5-Eirene and EMC3-Eirene codes

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, J., E-mail: rappj@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States); Owen, L.W. [Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States); Bonnin, X. [LSPM-CNRS, Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse (France); Caneses, J.F. [PRL, Research School of Physics and Engineering, ANU, Canberra (Australia); Canik, J.M. [Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States); Corr, C. [PRL, Research School of Physics and Engineering, ANU, Canberra (Australia); Lore, J.D. [Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States)

    2015-08-15

    Linear plasma generators are cost effective facilities to simulate divertor plasma conditions of present and future fusion reactors. The codes B2.5-Eirene and EMC3-Eirene were extensively used for design studies of the planned Material Plasma Exposure eXperiment (MPEX). Effects on the target plasma of the gas fueling and pumping locations, heating power, device length, magnetic configuration and transport model were studied with B2.5-Eirene. Effects of tilted or vertical targets were calculated with EMC3-Eirene and showed that spreading the incident flux over a larger area leads to lower density, higher temperature and off-axis profile peaking in front of the target. The simulations indicate that with sufficient heating power MPEX can reach target plasma conditions that are similar to those expected in the ITER divertor. B2.5-Eirene simulations of the MAGPIE experiment have been carried out in order to establish an additional benchmark with experimental data from a linear device with helicon wave heating.

  19. An energy-efficient process for decomposing perfluorooctanoic and perfluorooctane sulfonic acids using dc plasmas generated within gas bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Yasuoka, K; Sasaki, K; Hayashi, R, E-mail: yasuoka@ee.titech.ac.jp [Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, Ookayama, Tokyo (Japan)

    2011-06-15

    Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are environmentally harmful and persistent substances. Their decomposition was investigated using dc plasmas generated within small gas bubbles in a solution. The plasma characteristics including discharge voltage, voltage drop in the liquid, plasma shape and the emission spectrum were examined with different gases. The decomposition rate and energy efficiency were evaluated by measuring the concentration of fluoride and sulfate ions released from PFOA/PFOS molecules. The concentration of fluoride ions and energy efficiency in the treatment of a PFOS solution were 17.7 mg l{sup -1} (54.8% of the initial amount of fluorine atoms) and 26 mg kWh{sup -1}, respectively, after 240 min of operation. The addition of scavengers of hydroxyl radicals and hydrated electrons showed little effect on the decomposition. The decomposition processes were analyzed with an assumption that positive species reacted with PFOA/PFOS molecules at the boundary of the plasma-solution surface. This type of plasma showed a much higher decomposition energy efficiency compared with energy efficiencies reported in other studies.

  20. A simulation study of interactions of space-shuttle generated electron beams with ambient plasma and neutral gas

    Science.gov (United States)

    Winglee, Robert M.

    1991-01-01

    The objective was to conduct large scale simulations of electron beams injected into space. The study of the active injection of electron beams from spacecraft is important, as it provides valuable insight into the plasma beam interactions and the development of current systems in the ionosphere. However, the beam injection itself is not simple, being constrained by the ability of the spacecraft to draw current from the ambient plasma. The generation of these return currents is dependent on several factors, including the density of the ambient plasma relative to the beam density, the presence of neutrals around the spacecraft, the configuration of the spacecraft, and the motion of the spacecraft through the plasma. Two dimensional (three velocity) particle simulations with collisional processes included are used to show how these different and often coupled processes can be used to enhance beam propagation from the spacecraft. To understand the radial expansion mechanism of an electron beam injected from a highly charged spacecraft, two dimensional particle-in-cell simulations were conducted for a high density electron beam injected parallel to magnetic fields from an isolated equipotential conductor into a cold background plasma. The simulations indicate that charge build-up at the beam stagnation point causes the beam to expand radially to the beam electron gyroradius.